Chargements de fichiers Blazor ASP.NET Core

Utilisateurs du conteneur Autofac d’inversion de contrôle (IoC)

Si vous utilisez le conteneur Autofac d’inversion de contrôle (IoC) au lieu du conteneur intégré d’injection de dépendances ASP.NET Core, définissez DisableImplicitFromServicesParameters sur true dans les options du hub de gestionnaire de circuit côté serveur. Pour plus d’informations, consultez FileUpload: Did not receive any data in the allotted time (dotnet/aspnetcore #38842).

Côté serveur ou côté client, il n’existe aucune limite de taille de lecture ou de chargement de fichier spécifiquement pour le composant InputFile. Toutefois, Blazor côté client lit les octets du fichier dans une mémoire tampon de taille fixe (Array Buffer) JavaScript unique pendant le marshaling des données de JavaScript à C#, limité à 2 Go ou à la mémoire disponible de l’appareil. Les chargements de fichiers volumineux (> 250 Mo) peuvent échouer pour les chargements côté client utilisant le composant InputFile. Pour plus d’informations, consultez les discussions suivantes :

La taille de fichier maximale prise en charge pour le composant InputFile est de 2 Go. En outre, Blazor côté client lit les octets du fichier dans une mémoire tampon de taille fixe (Array Buffer) JavaScript unique pendant le marshaling des données de JavaScript à C#, limité à 2 Go ou à la mémoire disponible de l’appareil. Les chargements de fichiers volumineux (> 250 Mo) peuvent échouer pour les chargements côté client utilisant le composant InputFile. Pour plus d’informations, consultez les discussions suivantes :

@page "/file-upload-1"
@using System 
@using System.IO
@using Microsoft.AspNetCore.Hosting
@inject ILogger<FileUpload1> Logger
@inject IWebHostEnvironment Environment

<PageTitle>File Upload 1</PageTitle>

<h1>File Upload Example 1</h1>

<p>
    <label>
        Max file size:
        <input type="number" @bind="maxFileSize" />
    </label>
</p>

<p>
    <label>
        Max allowed files:
        <input type="number" @bind="maxAllowedFiles" />
    </label>
</p>

<p>
    <label>
        Upload up to @maxAllowedFiles of up to @maxFileSize bytes:
        <InputFile OnChange="LoadFiles" multiple />
    </label>
</p>

@if (isLoading)
{
    <p>Uploading...</p>
}
else
{
    <ul>
        @foreach (var file in loadedFiles)
        {
            <li>
                <ul>
                    <li>Name: @file.Name</li>
                    <li>Last modified: @file.LastModified.ToString()</li>
                    <li>Size (bytes): @file.Size</li>
                    <li>Content type: @file.ContentType</li>
                </ul>
            </li>
        }
    </ul>
}

@code {
    private List<IBrowserFile> loadedFiles = new();
    private long maxFileSize = 1024 * 15;
    private int maxAllowedFiles = 3;
    private bool isLoading;

    private async Task LoadFiles(InputFileChangeEventArgs e)
    {
        isLoading = true;
        loadedFiles.Clear();

        foreach (var file in e.GetMultipleFiles(maxAllowedFiles))
        {
            try
            {
                var trustedFileName = Path.GetRandomFileName();
                var path = Path.Combine(Environment.ContentRootPath,
                    Environment.EnvironmentName, "unsafe_uploads",
                    trustedFileName);

                await using FileStream fs = new(path, FileMode.Create);
                await file.OpenReadStream(maxFileSize).CopyToAsync(fs);

                loadedFiles.Add(file);

                Logger.LogInformation(
                    "Unsafe Filename: {UnsafeFilename} File saved: {Filename}",
                    file.Name, trustedFileName);
            }
            catch (Exception ex)
            {
                Logger.LogError("File: {Filename} Error: {Error}", 
                    file.Name, ex.Message);
            }
        }

        isLoading = false;
    }
}

@page "/file-upload-1"
@using System 
@using System.IO
@using Microsoft.AspNetCore.Hosting
@using Microsoft.Extensions.Logging
@inject ILogger<FileUpload1> Logger
@inject IWebHostEnvironment Environment

<h3>Upload Files</h3>

<p>
    <label>
        Max file size:
        <input type="number" @bind="maxFileSize" />
    </label>
</p>

<p>
    <label>
        Max allowed files:
        <input type="number" @bind="maxAllowedFiles" />
    </label>
</p>

<p>
    <label>
        Upload up to @maxAllowedFiles of up to @maxFileSize bytes:
        <InputFile OnChange="LoadFiles" multiple />
    </label>
</p>

@if (isLoading)
{
    <p>Uploading...</p>
}
else
{
    <ul>
        @foreach (var file in loadedFiles)
        {
            <li>
                <ul>
                    <li>Name: @file.Name</li>
                    <li>Last modified: @file.LastModified.ToString()</li>
                    <li>Size (bytes): @file.Size</li>
                    <li>Content type: @file.ContentType</li>
                </ul>
            </li>
        }
    </ul>
}

@code {
    private List<IBrowserFile> loadedFiles = new();
    private long maxFileSize = 1024 * 15;
    private int maxAllowedFiles = 3;
    private bool isLoading;

    private async Task LoadFiles(InputFileChangeEventArgs e)
    {
        isLoading = true;
        loadedFiles.Clear();

        foreach (var file in e.GetMultipleFiles(maxAllowedFiles))
        {
            try
            {
                loadedFiles.Add(file);

                var trustedFileNameForFileStorage = Path.GetRandomFileName();
                var path = Path.Combine(Environment.ContentRootPath,
                        Environment.EnvironmentName, "unsafe_uploads",
                        trustedFileNameForFileStorage);

                await using FileStream fs = new(path, FileMode.Create);
                await file.OpenReadStream(maxFileSize).CopyToAsync(fs);
            }
            catch (Exception ex)
            {
                Logger.LogError("File: {Filename} Error: {Error}", 
                    file.Name, ex.Message);
            }
        }

        isLoading = false;
    }
}

@page "/file-upload-1"
@using System 
@using System.IO
@using Microsoft.AspNetCore.Hosting
@using Microsoft.Extensions.Logging
@inject ILogger<FileUpload1> Logger
@inject IWebHostEnvironment Environment

<h3>Upload Files</h3>

<p>
    <label>
        Max file size:
        <input type="number" @bind="maxFileSize" />
    </label>
</p>

<p>
    <label>
        Max allowed files:
        <input type="number" @bind="maxAllowedFiles" />
    </label>
</p>

<p>
    <label>
        Upload up to @maxAllowedFiles of up to @maxFileSize bytes:
        <InputFile OnChange="LoadFiles" multiple />
    </label>
</p>

@if (isLoading)
{
    <p>Uploading...</p>
}
else
{
    <ul>
        @foreach (var file in loadedFiles)
        {
            <li>
                <ul>
                    <li>Name: @file.Name</li>
                    <li>Last modified: @file.LastModified.ToString()</li>
                    <li>Size (bytes): @file.Size</li>
                    <li>Content type: @file.ContentType</li>
                </ul>
            </li>
        }
    </ul>
}

@code {
    private List<IBrowserFile> loadedFiles = new();
    private long maxFileSize = 1024 * 15;
    private int maxAllowedFiles = 3;
    private bool isLoading;

    private async Task LoadFiles(InputFileChangeEventArgs e)
    {
        isLoading = true;
        loadedFiles.Clear();

        foreach (var file in e.GetMultipleFiles(maxAllowedFiles))
        {
            try
            {
                loadedFiles.Add(file);

                var trustedFileNameForFileStorage = Path.GetRandomFileName();
                var path = Path.Combine(Environment.ContentRootPath,
                        Environment.EnvironmentName, "unsafe_uploads",
                        trustedFileNameForFileStorage);

                await using FileStream fs = new(path, FileMode.Create);
                await file.OpenReadStream(maxFileSize).CopyToAsync(fs);
            }
            catch (Exception ex)
            {
                Logger.LogError("File: {Filename} Error: {Error}", 
                    file.Name, ex.Message);
            }
        }

        isLoading = false;
    }
}

@page "/file-upload-1"
@using System 
@using System.IO
@using Microsoft.AspNetCore.Hosting
@using Microsoft.Extensions.Logging
@inject ILogger<FileUpload1> Logger
@inject IWebHostEnvironment Environment

<h3>Upload Files</h3>

<p>
    <label>
        Max file size:
        <input type="number" @bind="maxFileSize" />
    </label>
</p>

<p>
    <label>
        Max allowed files:
        <input type="number" @bind="maxAllowedFiles" />
    </label>
</p>

<p>
    <label>
        Upload up to @maxAllowedFiles of up to @maxFileSize bytes:
        <InputFile OnChange="LoadFiles" multiple />
    </label>
</p>

@if (isLoading)
{
    <p>Uploading...</p>
}
else
{
    <ul>
        @foreach (var file in loadedFiles)
        {
            <li>
                <ul>
                    <li>Name: @file.Name</li>
                    <li>Last modified: @file.LastModified.ToString()</li>
                    <li>Size (bytes): @file.Size</li>
                    <li>Content type: @file.ContentType</li>
                </ul>
            </li>
        }
    </ul>
}

@code {
    private List<IBrowserFile> loadedFiles = new();
    private long maxFileSize = 1024 * 15;
    private int maxAllowedFiles = 3;
    private bool isLoading;

    private async Task LoadFiles(InputFileChangeEventArgs e)
    {
        isLoading = true;
        loadedFiles.Clear();

        foreach (var file in e.GetMultipleFiles(maxAllowedFiles))
        {
            try
            {
                loadedFiles.Add(file);

                var trustedFileNameForFileStorage = Path.GetRandomFileName();
                var path = Path.Combine(Environment.ContentRootPath,
                        Environment.EnvironmentName, "unsafe_uploads",
                        trustedFileNameForFileStorage);

                await using FileStream fs = new(path, FileMode.Create);
                await file.OpenReadStream(maxFileSize).CopyToAsync(fs);
            }
            catch (Exception ex)
            {
                Logger.LogError("File: {Filename} Error: {Error}", 
                    file.Name, ex.Message);
            }
        }

        isLoading = false;
    }
}

@page "/file-upload-1"
@inject ILogger<FileUpload1> Logger

<PageTitle>File Upload 1</PageTitle>

<h1>File Upload Example 1</h1>

<p>
    <label>
        Max file size:
        <input type="number" @bind="maxFileSize" />
    </label>
</p>

<p>
    <label>
        Max allowed files:
        <input type="number" @bind="maxAllowedFiles" />
    </label>
</p>

<p>
    <label>
        Upload up to @maxAllowedFiles of up to @maxFileSize bytes:
        <InputFile OnChange="LoadFiles" multiple />
    </label>
</p>

@if (isLoading)
{
    <p>Uploading...</p>
}
else
{
    <ul>
        @foreach (var file in loadedFiles)
        {
            <li>
                <ul>
                    <li>Name: @file.Name</li>
                    <li>Last modified: @file.LastModified.ToString()</li>
                    <li>Size (bytes): @file.Size</li>
                    <li>Content type: @file.ContentType</li>
                </ul>
            </li>
        }
    </ul>
}

@code {
    private List<IBrowserFile> loadedFiles = new();
    private long maxFileSize = 1024 * 15;
    private int maxAllowedFiles = 3;
    private bool isLoading;

    private void LoadFiles(InputFileChangeEventArgs e)
    {
        isLoading = true;
        loadedFiles.Clear();

        foreach (var file in e.GetMultipleFiles(maxAllowedFiles))
        {
            try
            {
                loadedFiles.Add(file);
            }
            catch (Exception ex)
            {
                Logger.LogError("File: {FileName} Error: {Error}", 
                    file.Name, ex.Message);
            }
        }

        isLoading = false;
    }
}

@page "/file-upload-1"
@using Microsoft.Extensions.Logging
@inject ILogger<FileUpload1> Logger

<h3>Upload Files</h3>

<p>
    <label>
        Max file size:
        <input type="number" @bind="maxFileSize" />
    </label>
</p>

<p>
    <label>
        Max allowed files:
        <input type="number" @bind="maxAllowedFiles" />
    </label>
</p>

<p>
    <label>
        Upload up to @maxAllowedFiles of up to @maxFileSize bytes:
        <InputFile OnChange="LoadFiles" multiple />
    </label>
</p>

@if (isLoading)
{
    <p>Uploading...</p>
}
else
{
    <ul>
        @foreach (var file in loadedFiles)
        {
            <li>
                <ul>
                    <li>Name: @file.Name</li>
                    <li>Last modified: @file.LastModified.ToString()</li>
                    <li>Size (bytes): @file.Size</li>
                    <li>Content type: @file.ContentType</li>
                </ul>
            </li>
        }
    </ul>
}

@code {
    private List<IBrowserFile> loadedFiles = new();
    private long maxFileSize = 1024 * 15;
    private int maxAllowedFiles = 3;
    private bool isLoading;

    private void LoadFiles(InputFileChangeEventArgs e)
    {
        isLoading = true;
        loadedFiles.Clear();

        foreach (var file in e.GetMultipleFiles(maxAllowedFiles))
        {
            try
            {
                loadedFiles.Add(file);
            }
            catch (Exception ex)
            {
                Logger.LogError("File: {FileName} Error: {Error}", 
                    file.Name, ex.Message);
            }
        }

        isLoading = false;
    }
}

@page "/file-upload-1"
@using Microsoft.Extensions.Logging
@inject ILogger<FileUpload1> Logger

<h3>Upload Files</h3>

<p>
    <label>
        Max file size:
        <input type="number" @bind="maxFileSize" />
    </label>
</p>

<p>
    <label>
        Max allowed files:
        <input type="number" @bind="maxAllowedFiles" />
    </label>
</p>

<p>
    <label>
        Upload up to @maxAllowedFiles of up to @maxFileSize bytes:
        <InputFile OnChange="LoadFiles" multiple />
    </label>
</p>

@if (isLoading)
{
    <p>Uploading...</p>
}
else
{
    <ul>
        @foreach (var file in loadedFiles)
        {
            <li>
                <ul>
                    <li>Name: @file.Name</li>
                    <li>Last modified: @file.LastModified.ToString()</li>
                    <li>Size (bytes): @file.Size</li>
                    <li>Content type: @file.ContentType</li>
                </ul>
            </li>
        }
    </ul>
}

@code {
    private List<IBrowserFile> loadedFiles = new();
    private long maxFileSize = 1024 * 15;
    private int maxAllowedFiles = 3;
    private bool isLoading;

    private void LoadFiles(InputFileChangeEventArgs e)
    {
        isLoading = true;
        loadedFiles.Clear();

        foreach (var file in e.GetMultipleFiles(maxAllowedFiles))
        {
            try
            {
                loadedFiles.Add(file);
            }
            catch (Exception ex)
            {
                Logger.LogError("File: {Filename} Error: {Error}", 
                    file.Name, ex.Message);
            }
        }

        isLoading = false;
    }
}

@page "/file-upload-1"
@using Microsoft.Extensions.Logging
@inject ILogger<FileUpload1> Logger

<h3>Upload Files</h3>

<p>
    <label>
        Max file size:
        <input type="number" @bind="maxFileSize" />
    </label>
</p>

<p>
    <label>
        Max allowed files:
        <input type="number" @bind="maxAllowedFiles" />
    </label>
</p>

<p>
    <label>
        Upload up to @maxAllowedFiles of up to @maxFileSize bytes:
        <InputFile OnChange="LoadFiles" multiple />
    </label>
</p>

@if (isLoading)
{
    <p>Uploading...</p>
}
else
{
    <ul>
        @foreach (var file in loadedFiles)
        {
            <li>
                <ul>
                    <li>Name: @file.Name</li>
                    <li>Last modified: @file.LastModified.ToString()</li>
                    <li>Size (bytes): @file.Size</li>
                    <li>Content type: @file.ContentType</li>
                </ul>
            </li>
        }
    </ul>
}

@code {
    private List<IBrowserFile> loadedFiles = new();
    private long maxFileSize = 1024 * 15;
    private int maxAllowedFiles = 3;
    private bool isLoading;

    private void LoadFiles(InputFileChangeEventArgs e)
    {
        isLoading = true;
        loadedFiles.Clear();

        foreach (var file in e.GetMultipleFiles(maxAllowedFiles))
        {
            try
            {
                loadedFiles.Add(file);
            }
            catch (Exception ex)
            {
                Logger.LogError("File: {Filename} Error: {Error}", 
                    file.Name, ex.Message);
            }
        }

        isLoading = false;
    }
}

using Microsoft.AspNetCore.Components.Forms;
using System.Diagnostics.CodeAnalysis;

namespace BlazorSample;

internal sealed class LazyBrowserFileStream(IBrowserFile file, int maxAllowedSize) 
    : Stream
{
    private readonly IBrowserFile file = file;
    private readonly int maxAllowedSize = maxAllowedSize;
    private Stream? underlyingStream;
    private bool isDisposed;

    public override bool CanRead => true;

    public override bool CanSeek => false;

    public override bool CanWrite => false;

    public override long Length => file.Size;

    public override long Position
    {
        get => underlyingStream?.Position ?? 0;
        set => throw new NotSupportedException();
    }

    public override void Flush() => underlyingStream?.Flush();

    public override Task<int> ReadAsync(byte[] buffer, int offset, int count, 
        CancellationToken cancellationToken)
    {
        EnsureStreamIsOpen();

        return underlyingStream.ReadAsync(buffer, offset, count, cancellationToken);
    }

    public override ValueTask<int> ReadAsync(Memory<byte> buffer, 
        CancellationToken cancellationToken = default)
    {
        EnsureStreamIsOpen();
        return underlyingStream.ReadAsync(buffer, cancellationToken);
    }

    [MemberNotNull(nameof(underlyingStream))]
    private void EnsureStreamIsOpen() => 
        underlyingStream ??= file.OpenReadStream(maxAllowedSize);

    protected override void Dispose(bool disposing)
    {
        if (isDisposed)
        {
            return;
        }

        underlyingStream?.Dispose();
        isDisposed = true;

        base.Dispose(disposing);
    }

    public override int Read(byte[] buffer, int offset, int count)
        => throw new NotSupportedException();

    public override long Seek(long offset, SeekOrigin origin)
        => throw new NotSupportedException();

    public override void SetLength(long value)
        => throw new NotSupportedException();

    public override void Write(byte[] buffer, int offset, int count)
        => throw new NotSupportedException();
}

using Microsoft.AspNetCore.Components.Forms;
using System.Diagnostics.CodeAnalysis;

namespace BlazorSample;

internal sealed class LazyBrowserFileStream : Stream
{
    private readonly IBrowserFile file;
    private readonly int maxAllowedSize;
    private Stream? underlyingStream;
    private bool isDisposed;

    public override bool CanRead => true;

    public override bool CanSeek => false;

    public override bool CanWrite => false;

    public override long Length => file.Size;

    public override long Position
    {
        get => underlyingStream?.Position ?? 0;
        set => throw new NotSupportedException();
    }

    public LazyBrowserFileStream(IBrowserFile file, int maxAllowedSize)
    {
        this.file = file;
        this.maxAllowedSize = maxAllowedSize;
    }

    public override void Flush()
    {
        underlyingStream?.Flush();
    }

    public override Task<int> ReadAsync(byte[] buffer, int offset, int count, 
        CancellationToken cancellationToken)
    {
        EnsureStreamIsOpen();

        return underlyingStream.ReadAsync(buffer, offset, count, cancellationToken);
    }

    public override ValueTask<int> ReadAsync(Memory<byte> buffer, 
        CancellationToken cancellationToken = default)
    {
        EnsureStreamIsOpen();
        return underlyingStream.ReadAsync(buffer, cancellationToken);
    }

    [MemberNotNull(nameof(underlyingStream))]
    private void EnsureStreamIsOpen()
    {
        underlyingStream ??= file.OpenReadStream(maxAllowedSize);
    }

    protected override void Dispose(bool disposing)
    {
        if (isDisposed)
        {
            return;
        }

        underlyingStream?.Dispose();
        isDisposed = true;

        base.Dispose(disposing);
    }

    public override int Read(byte[] buffer, int offset, int count)
        => throw new NotSupportedException();

    public override long Seek(long offset, SeekOrigin origin)
        => throw new NotSupportedException();

    public override void SetLength(long value)
        => throw new NotSupportedException();

    public override void Write(byte[] buffer, int offset, int count)
        => throw new NotSupportedException();
}

using Microsoft.AspNetCore.Components.Forms;
using System.Diagnostics.CodeAnalysis;

namespace BlazorSample;

internal sealed class LazyBrowserFileStream : Stream
{
    private readonly IBrowserFile file;
    private readonly int maxAllowedSize;
    private Stream? underlyingStream;
    private bool isDisposed;

    public override bool CanRead => true;

    public override bool CanSeek => false;

    public override bool CanWrite => false;

    public override long Length => file.Size;

    public override long Position
    {
        get => underlyingStream?.Position ?? 0;
        set => throw new NotSupportedException();
    }

    public LazyBrowserFileStream(IBrowserFile file, int maxAllowedSize)
    {
        this.file = file;
        this.maxAllowedSize = maxAllowedSize;
    }

    public override void Flush()
    {
        underlyingStream?.Flush();
    }

    public override Task<int> ReadAsync(byte[] buffer, int offset, int count, 
        CancellationToken cancellationToken)
    {
        EnsureStreamIsOpen();

        return underlyingStream.ReadAsync(buffer, offset, count, cancellationToken);
    }

    public override ValueTask<int> ReadAsync(Memory<byte> buffer, 
        CancellationToken cancellationToken = default)
    {
        EnsureStreamIsOpen();
        return underlyingStream.ReadAsync(buffer, cancellationToken);
    }

    [MemberNotNull(nameof(underlyingStream))]
    private void EnsureStreamIsOpen()
    {
        underlyingStream ??= file.OpenReadStream(maxAllowedSize);
    }

    protected override void Dispose(bool disposing)
    {
        if (isDisposed)
        {
            return;
        }

        underlyingStream?.Dispose();
        isDisposed = true;

        base.Dispose(disposing);
    }

    public override int Read(byte[] buffer, int offset, int count)
        => throw new NotSupportedException();

    public override long Seek(long offset, SeekOrigin origin)
        => throw new NotSupportedException();

    public override void SetLength(long value)
        => throw new NotSupportedException();

    public override void Write(byte[] buffer, int offset, int count)
        => throw new NotSupportedException();
}

using System;
using System.Diagnostics.CodeAnalysis;
using System.IO;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Components.Forms;

namespace BlazorSample;

internal sealed class LazyBrowserFileStream : Stream
{
    private readonly IBrowserFile file;
    private readonly int maxAllowedSize;
    private Stream? underlyingStream;
    private bool isDisposed;

    public override bool CanRead => true;

    public override bool CanSeek => false;

    public override bool CanWrite => false;

    public override long Length => file.Size;

    public override long Position
    {
        get => underlyingStream?.Position ?? 0;
        set => throw new NotSupportedException();
    }

    public LazyBrowserFileStream(IBrowserFile file, int maxAllowedSize)
    {
        this.file = file;
        this.maxAllowedSize = maxAllowedSize;
    }

    public override void Flush()
    {
        underlyingStream?.Flush();
    }

    public override Task<int> ReadAsync(byte[] buffer, int offset, int count, 
        CancellationToken cancellationToken)
    {
        EnsureStreamIsOpen();

        return underlyingStream.ReadAsync(buffer, offset, count, cancellationToken);
    }

    public override ValueTask<int> ReadAsync(Memory<byte> buffer, 
        CancellationToken cancellationToken = default)
    {
        EnsureStreamIsOpen();
        return underlyingStream.ReadAsync(buffer, cancellationToken);
    }

    [MemberNotNull(nameof(underlyingStream))]
    private void EnsureStreamIsOpen()
    {
        underlyingStream ??= file.OpenReadStream(maxAllowedSize);
    }

    protected override void Dispose(bool disposing)
    {
        if (isDisposed)
        {
            return;
        }

        underlyingStream?.Dispose();
        isDisposed = true;

        base.Dispose(disposing);
    }

    public override int Read(byte[] buffer, int offset, int count)
        => throw new NotSupportedException();

    public override long Seek(long offset, SeekOrigin origin)
        => throw new NotSupportedException();

    public override void SetLength(long value)
        => throw new NotSupportedException();

    public override void Write(byte[] buffer, int offset, int count)
        => throw new NotSupportedException();
}

@page "/file-upload-2"
@using System.Net.Http.Headers
@using System.Text.Json
@inject IHttpClientFactory ClientFactory
@inject ILogger<FileUpload2> Logger

<PageTitle>File Upload 2</PageTitle>

<h1>File Upload Example 2</h1>

<p>
    This example requires a backend server API to function. For more information, 
    see the <em>Upload files to a server</em> section 
    of the <em>ASP.NET Core Blazor file uploads</em> article.
</p>

<p>
    <label>
        Upload up to @maxAllowedFiles files:
        <InputFile OnChange="OnInputFileChange" multiple />
    </label>
</p>

@if (files.Any())
{
    <div class="card">
        <div class="card-body">
            <ul>
                @foreach (var file in files)
                {
                    <li>
                        File: @file.Name
                        <br>
                        @if (FileUpload(uploadResults, file.Name, Logger,
                           out var result))
                        {
                            <span>
                                Stored File Name: @result.StoredFileName
                            </span>
                        }
                        else
                        {
                            <span>
                                There was an error uploading the file
                                (Error: @result.ErrorCode).
                            </span>
                        }
                    </li>
                }
            </ul>
        </div>
    </div>
}

@code {
    private List<File> files = new();
    private List<UploadResult> uploadResults = new();
    private int maxAllowedFiles = 3;
    private bool shouldRender;

    protected override bool ShouldRender() => shouldRender;

    private async Task OnInputFileChange(InputFileChangeEventArgs e)
    {
        shouldRender = false;
        int maxFileSize = 1024 * 15;
        var upload = false;

        using var content = new MultipartFormDataContent();

        foreach (var file in e.GetMultipleFiles(maxAllowedFiles))
        {
            if (uploadResults.SingleOrDefault(
                f => f.FileName == file.Name) is null)
            {
                try
                {
                    files.Add(new() { Name = file.Name });

                    var stream = new LazyBrowserFileStream(file, maxFileSize);
                    var fileContent = new StreamContent(stream);

                    fileContent.Headers.ContentType = 
                        new MediaTypeHeaderValue(file.ContentType);

                    content.Add(
                        content: fileContent,
                        name: "\"files\"",
                        fileName: file.Name);

                    upload = true;
                }
                catch (Exception ex)
                {
                    Logger.LogInformation(
                        "{FileName} not uploaded (Err: 6): {Message}", 
                        file.Name, ex.Message);

                    uploadResults.Add(
                        new()
                        {
                            FileName = file.Name, 
                            ErrorCode = 6, 
                            Uploaded = false
                        });
                }
            }
        }

        if (upload)
        {
            var client = ClientFactory.CreateClient();

            var response = 
                await client.PostAsync("https://localhost:5001/Filesave", 
                content);

            if (response.IsSuccessStatusCode)
            {
                var options = new JsonSerializerOptions
                {
                    PropertyNameCaseInsensitive = true,
                };

                using var responseStream =
                    await response.Content.ReadAsStreamAsync();

                var newUploadResults = await JsonSerializer
                    .DeserializeAsync<IList<UploadResult>>(responseStream, options);

                if (newUploadResults is not null)
                {
                    uploadResults = uploadResults.Concat(newUploadResults).ToList();
                }
            }
        }

        shouldRender = true;
    }

    private static bool FileUpload(IList<UploadResult> uploadResults,
        string? fileName, ILogger<FileUpload2> logger, out UploadResult result)
    {
        result = uploadResults.SingleOrDefault(f => f.FileName == fileName) ?? new();

        if (!result.Uploaded)
        {
            logger.LogInformation("{FileName} not uploaded (Err: 5)", fileName);
            result.ErrorCode = 5;
        }

        return result.Uploaded;
    }

    private class File
    {
        public string? Name { get; set; }
    }
}

@page "/file-upload-2"
@using System.Net.Http.Headers
@using System.Text.Json
@inject IHttpClientFactory ClientFactory
@inject ILogger<FileUpload2> Logger

<h1>File Upload Example 2</h1>

<p>
    This example requires a backend server API to function. For more information, 
    see the <em>Upload files to a server</em> section 
    of the <em>ASP.NET Core Blazor file uploads</em> article.
</p>

<p>
    <label>
        Upload up to @maxAllowedFiles files:
        <InputFile OnChange="OnInputFileChange" multiple />
    </label>
</p>

@if (files.Count > 0)
{
    <div class="card">
        <div class="card-body">
            <ul>
                @foreach (var file in files)
                {
                    <li>
                        File: @file.Name
                        <br>
                        @if (FileUpload(uploadResults, file.Name, Logger,
                           out var result))
                        {
                            <span>
                                Stored File Name: @result.StoredFileName
                            </span>
                        }
                        else
                        {
                            <span>
                                There was an error uploading the file
                                (Error: @result.ErrorCode).
                            </span>
                        }
                    </li>
                }
            </ul>
        </div>
    </div>
}

@code {
    private List<File> files = new();
    private List<UploadResult> uploadResults = new();
    private int maxAllowedFiles = 3;
    private bool shouldRender;

    protected override bool ShouldRender() => shouldRender;

    private async Task OnInputFileChange(InputFileChangeEventArgs e)
    {
        shouldRender = false;
        int maxFileSize = 1024 * 15;
        var upload = false;

        using var content = new MultipartFormDataContent();

        foreach (var file in e.GetMultipleFiles(maxAllowedFiles))
        {
            if (uploadResults.SingleOrDefault(
                f => f.FileName == file.Name) is null)
            {
                try
                {
                    files.Add(new() { Name = file.Name });

                    var stream = new LazyBrowserFileStream(file, maxFileSize);
                    var fileContent = new StreamContent(stream);
                    fileContent.Headers.ContentType = 
                        new MediaTypeHeaderValue(file.ContentType);

                    content.Add(
                        content: fileContent,
                        name: "\"files\"",
                        fileName: file.Name);

                    upload = true;
                }
                catch (Exception ex)
                {
                    Logger.LogInformation(
                        "{FileName} not uploaded (Err: 6): {Message}", 
                        file.Name, ex.Message);

                    uploadResults.Add(
                        new()
                        {
                            FileName = file.Name, 
                            ErrorCode = 6, 
                            Uploaded = false
                        });
                }
            }
        }

        if (upload)
        {
            var client = ClientFactory.CreateClient();

            var response = 
                await client.PostAsync("https://localhost:5001/Filesave", 
                content);

            if (response.IsSuccessStatusCode)
            {
                var options = new JsonSerializerOptions
                {
                    PropertyNameCaseInsensitive = true,
                };

                using var responseStream =
                    await response.Content.ReadAsStreamAsync();

                var newUploadResults = await JsonSerializer
                    .DeserializeAsync<IList<UploadResult>>(responseStream, options);

                if (newUploadResults is not null)
                {
                    uploadResults = uploadResults.Concat(newUploadResults).ToList();
                }
            }
        }

        shouldRender = true;
    }

    private static bool FileUpload(IList<UploadResult> uploadResults,
        string? fileName, ILogger<FileUpload2> logger, out UploadResult result)
    {
        result = uploadResults.SingleOrDefault(f => f.FileName == fileName) ?? new();

        if (!result.Uploaded)
        {
            logger.LogInformation("{FileName} not uploaded (Err: 5)", fileName);
            result.ErrorCode = 5;
        }

        return result.Uploaded;
    }

    private class File
    {
        public string? Name { get; set; }
    }
}

@page "/file-upload-2"
@using System.Net.Http.Headers
@using System.Text.Json
@inject IHttpClientFactory ClientFactory
@inject ILogger<FileUpload2> Logger

<h1>File Upload Example 2</h1>

<p>
    This example requires a backend server API to function. For more information, 
    see the <em>Upload files to a server</em> section 
    of the <em>ASP.NET Core Blazor file uploads</em> article.
</p>

<p>
    <label>
        Upload up to @maxAllowedFiles files:
        <InputFile OnChange="OnInputFileChange" multiple />
    </label>
</p>

@if (files.Count > 0)
{
    <div class="card">
        <div class="card-body">
            <ul>
                @foreach (var file in files)
                {
                    <li>
                        File: @file.Name
                        <br>
                        @if (FileUpload(uploadResults, file.Name, Logger,
                           out var result))
                        {
                            <span>
                                Stored File Name: @result.StoredFileName
                            </span>
                        }
                        else
                        {
                            <span>
                                There was an error uploading the file
                                (Error: @result.ErrorCode).
                            </span>
                        }
                    </li>
                }
            </ul>
        </div>
    </div>
}

@code {
    private List<File> files = new();
    private List<UploadResult> uploadResults = new();
    private int maxAllowedFiles = 3;
    private bool shouldRender;

    protected override bool ShouldRender() => shouldRender;

    private async Task OnInputFileChange(InputFileChangeEventArgs e)
    {
        shouldRender = false;
        int maxFileSize = 1024 * 15;
        var upload = false;

        using var content = new MultipartFormDataContent();

        foreach (var file in e.GetMultipleFiles(maxAllowedFiles))
        {
            if (uploadResults.SingleOrDefault(
                f => f.FileName == file.Name) is null)
            {
                try
                {
                    files.Add(new() { Name = file.Name });

                    var stream = new LazyBrowserFileStream(file, maxFileSize);
                    var fileContent = new StreamContent(stream);
                    fileContent.Headers.ContentType = 
                        new MediaTypeHeaderValue(file.ContentType);

                    content.Add(
                        content: fileContent,
                        name: "\"files\"",
                        fileName: file.Name);

                    upload = true;
                }
                catch (Exception ex)
                {
                    Logger.LogInformation(
                        "{FileName} not uploaded (Err: 6): {Message}", 
                        file.Name, ex.Message);

                    uploadResults.Add(
                        new()
                        {
                            FileName = file.Name, 
                            ErrorCode = 6, 
                            Uploaded = false
                        });
                }
            }
        }

        if (upload)
        {
            var client = ClientFactory.CreateClient();

            var response = 
                await client.PostAsync("https://localhost:5001/Filesave", 
                content);

            if (response.IsSuccessStatusCode)
            {
                var options = new JsonSerializerOptions
                {
                    PropertyNameCaseInsensitive = true,
                };

                using var responseStream =
                    await response.Content.ReadAsStreamAsync();

                var newUploadResults = await JsonSerializer
                    .DeserializeAsync<IList<UploadResult>>(responseStream, options);

                if (newUploadResults is not null)
                {
                    uploadResults = uploadResults.Concat(newUploadResults).ToList();
                }
            }
        }

        shouldRender = true;
    }

    private static bool FileUpload(IList<UploadResult> uploadResults,
        string? fileName, ILogger<FileUpload2> logger, out UploadResult result)
    {
        result = uploadResults.SingleOrDefault(f => f.FileName == fileName) ?? new();

        if (!result.Uploaded)
        {
            logger.LogInformation("{FileName} not uploaded (Err: 5)", fileName);
            result.ErrorCode = 5;
        }

        return result.Uploaded;
    }

    private class File
    {
        public string? Name { get; set; }
    }
}

@page "/file-upload-2"
@using System.Net.Http.Headers
@using System.Text.Json
@using Microsoft.Extensions.Logging
@inject IHttpClientFactory ClientFactory
@inject ILogger<FileUpload2> Logger

<h1>File Upload Example 2</h1>

<p>
    This example requires a backend server API to function. For more information, 
    see the <em>Upload files to a server</em> section 
    of the <em>ASP.NET Core Blazor file uploads</em> article.
</p>

<p>
    <label>
        Upload up to @maxAllowedFiles files:
        <InputFile OnChange="OnInputFileChange" multiple />
    </label>
</p>

@if (files.Count > 0)
{
    <div class="card">
        <div class="card-body">
            <ul>
                @foreach (var file in files)
                {
                    <li>
                        File: @file.Name
                        <br>
                        @if (FileUpload(uploadResults, file.Name, Logger,
                           out var result))
                        {
                            <span>
                                Stored File Name: @result.StoredFileName
                            </span>
                        }
                        else
                        {
                            <span>
                                There was an error uploading the file
                                (Error: @result.ErrorCode).
                            </span>
                        }
                    </li>
                }
            </ul>
        </div>
    </div>
}

@code {
    private List<File> files = new();
    private List<UploadResult> uploadResults = new();
    private int maxAllowedFiles = 3;
    private bool shouldRender;

    protected override bool ShouldRender() => shouldRender;

    private async Task OnInputFileChange(InputFileChangeEventArgs e)
    {
        shouldRender = false;
        int maxFileSize = 1024 * 15;
        var upload = false;

        using var content = new MultipartFormDataContent();

        foreach (var file in e.GetMultipleFiles(maxAllowedFiles))
        {
            if (uploadResults.SingleOrDefault(
                f => f.FileName == file.Name) is null)
            {
                try
                {
                    files.Add(new() { Name = file.Name });

                    var stream = new LazyBrowserFileStream(file, maxFileSize);
                    var fileContent = new StreamContent(stream);
                    fileContent.Headers.ContentType = 
                        new MediaTypeHeaderValue(file.ContentType);

                    content.Add(
                        content: fileContent,
                        name: "\"files\"",
                        fileName: file.Name);

                    upload = true;
                }
                catch (Exception ex)
                {
                    Logger.LogInformation(
                        "{FileName} not uploaded (Err: 6): {Message}", 
                        file.Name, ex.Message);

                    uploadResults.Add(
                        new()
                        {
                            FileName = file.Name, 
                            ErrorCode = 6, 
                            Uploaded = false
                        });
                }
            }
        }

        if (upload)
        {
            var client = ClientFactory.CreateClient();

            var response = 
                await client.PostAsync("https://localhost:5001/Filesave", 
                content);

            if (response.IsSuccessStatusCode)
            {
                var options = new JsonSerializerOptions
                {
                    PropertyNameCaseInsensitive = true,
                };

                using var responseStream =
                    await response.Content.ReadAsStreamAsync();

                var newUploadResults = await JsonSerializer
                    .DeserializeAsync<IList<UploadResult>>(responseStream, options);

                if (newUploadResults is not null)
                {
                    uploadResults = uploadResults.Concat(newUploadResults).ToList();
                }
            }
        }

        shouldRender = true;
    }

    private static bool FileUpload(IList<UploadResult> uploadResults,
        string fileName, ILogger<FileUpload2> logger, out UploadResult result)
    {
        result = uploadResults.SingleOrDefault(f => f.FileName == fileName) ?? new();

        if (!result.Uploaded)
        {
            logger.LogInformation("{FileName} not uploaded (Err: 5)", fileName);
            result.ErrorCode = 5;
        }

        return result.Uploaded;
    }

    private class File
    {
        public string Name { get; set; }
    }
}

Si le composant limite les chargements de fichiers à un seul fichier à la fois ou s’il adopte uniquement le rendu interactif côté client (RSC, InteractiveWebAssembly), le composant peut éviter l’utilisation du LazyBrowserFileStream et utiliser un Stream. Voici les modifications apportées au composant FileUpload2 :

- var stream = new LazyBrowserFileStream(file, maxFileSize);
- var fileContent = new StreamContent(stream);
+ var fileContent = new StreamContent(file.OpenReadStream(maxFileSize));

Supprimez la classe LazyBrowserFileStream (LazyBrowserFileStream.cs), car elle n’est pas utilisée.

Si le composant limite les chargements de fichiers à un seul fichier à la fois, le composant peut éviter l’utilisation du LazyBrowserFileStream et utiliser un Stream. Voici les modifications apportées au composant FileUpload2 :

- var stream = new LazyBrowserFileStream(file, maxFileSize);
- var fileContent = new StreamContent(stream);
+ var fileContent = new StreamContent(file.OpenReadStream(maxFileSize));

Supprimez la classe LazyBrowserFileStream (LazyBrowserFileStream.cs), car elle n’est pas utilisée.

Dans le projet principal Blazor Web App, ajoutez IHttpClientFactory et les services associés dans le fichier Program du projet :

builder.Services.AddHttpClient();

Les services HttpClient doivent être ajoutés au projet principal, car le composant côté client est pré-affiché sur le serveur. Si vous désactivez le pré-affichage pour le composant suivant, vous n’êtes pas obligé de fournir les services HttpClient dans l’application principale et vous n’avez pas besoin d’ajouter la ligne précédente au projet principal.

Pour obtenir plus d’informations sur l’ajout des services HttpClient à une application ASP.NET Core, consultez Effectuer des requêtes HTTP en utilisant IHttpClientFactory dans ASP.NET Core.

Le projet de client (.Client) d’une Blazor Web App doit également inscrire un HttpClient pour les requêtes HTTP POST auprès d’un contrôleur d’API web back-end. Validez ou ajoutez ce qui suit au fichier Program du projet de client :

builder.Services.AddScoped(sp => 
    new HttpClient { BaseAddress = new Uri(builder.HostEnvironment.BaseAddress) });

L’exemple précédent définit l’adresse de base avec builder.HostEnvironment.BaseAddress (IWebAssemblyHostEnvironment.BaseAddress). Cette propriété récupère l’adresse de base de l’application. Elle est généralement dérivée de la valeur href de la balise <base> dans la page hôte. Si vous appelez une API web externe, définissez l’URI sur l’adresse de base de l’API web.

Spécifiez l’attribut de mode de rendu WebAssembly interactif en haut du composant suivant dans une Blazor Web App :

@rendermode InteractiveWebAssembly

@page "/file-upload-2"
@using System.Linq
@using System.Net.Http.Headers
@inject HttpClient Http
@inject ILogger<FileUpload2> Logger

<PageTitle>File Upload 2</PageTitle>

<h1>File Upload Example 2</h1>

<p>
    <label>
        Upload up to @maxAllowedFiles files:
        <InputFile OnChange="OnInputFileChange" multiple />
    </label>
</p>

@if (files.Count > 0)
{
    <div class="card">
        <div class="card-body">
            <ul>
                @foreach (var file in files)
                {
                    <li>
                        File: @file.Name
                        <br>
                        @if (FileUpload(uploadResults, file.Name, Logger,
                           out var result))
                        {
                            <span>
                                Stored File Name: @result.StoredFileName
                            </span>
                        }
                        else
                        {
                            <span>
                                There was an error uploading the file
                                (Error: @result.ErrorCode).
                            </span>
                        }
                    </li>
                }
            </ul>
        </div>
    </div>
}

@code {
    private List<File> files = new();
    private List<UploadResult> uploadResults = new();
    private int maxAllowedFiles = 3;
    private bool shouldRender;

    protected override bool ShouldRender() => shouldRender;

    private async Task OnInputFileChange(InputFileChangeEventArgs e)
    {
        shouldRender = false;
        long maxFileSize = 1024 * 15;
        var upload = false;

        using var content = new MultipartFormDataContent();

        foreach (var file in e.GetMultipleFiles(maxAllowedFiles))
        {
            if (uploadResults.SingleOrDefault(
                f => f.FileName == file.Name) is null)
            {
                try
                {
                    files.Add(new() { Name = file.Name });

                    var fileContent = new StreamContent(file.OpenReadStream(maxFileSize));

                    fileContent.Headers.ContentType = 
                        new MediaTypeHeaderValue(file.ContentType);

                    content.Add(
                        content: fileContent,
                        name: "\"files\"",
                        fileName: file.Name);

                    upload = true;
                }
                catch (Exception ex)
                {
                    Logger.LogInformation(
                        "{FileName} not uploaded (Err: 6): {Message}", 
                        file.Name, ex.Message);

                    uploadResults.Add(
                        new()
                        {
                            FileName = file.Name, 
                            ErrorCode = 6, 
                            Uploaded = false
                        });
                }
            }
        }

        if (upload)
        {
            var response = await Http.PostAsync("/Filesave", content);

            var newUploadResults = await response.Content
                .ReadFromJsonAsync<IList<UploadResult>>();

            if (newUploadResults is not null)
            {
                uploadResults = uploadResults.Concat(newUploadResults).ToList();
            }
        }

        shouldRender = true;
    }

    private static bool FileUpload(IList<UploadResult> uploadResults,
        string? fileName, ILogger<FileUpload2> logger, out UploadResult result)
    {
        result = uploadResults.SingleOrDefault(f => f.FileName == fileName) ?? new();

        if (!result.Uploaded)
        {
            logger.LogInformation("{FileName} not uploaded (Err: 5)", fileName);
            result.ErrorCode = 5;
        }

        return result.Uploaded;
    }

    private class File
    {
        public string? Name { get; set; }
    }
}

@page "/file-upload-2"
@using System.Linq
@using System.Net.Http.Headers
@using Microsoft.Extensions.Logging
@inject HttpClient Http
@inject ILogger<FileUpload2> Logger

<h1>Upload Files</h1>

<p>
    <label>
        Upload up to @maxAllowedFiles files:
        <InputFile OnChange="OnInputFileChange" multiple />
    </label>
</p>

@if (files.Count > 0)
{
    <div class="card">
        <div class="card-body">
            <ul>
                @foreach (var file in files)
                {
                    <li>
                        File: @file.Name
                        <br>
                        @if (FileUpload(uploadResults, file.Name, Logger,
                           out var result))
                        {
                            <span>
                                Stored File Name: @result.StoredFileName
                            </span>
                        }
                        else
                        {
                            <span>
                                There was an error uploading the file
                                (Error: @result.ErrorCode).
                            </span>
                        }
                    </li>
                }
            </ul>
        </div>
    </div>
}

@code {
    private List<File> files = new();
    private List<UploadResult> uploadResults = new();
    private int maxAllowedFiles = 3;
    private bool shouldRender;

    protected override bool ShouldRender() => shouldRender;

    private async Task OnInputFileChange(InputFileChangeEventArgs e)
    {
        shouldRender = false;
        long maxFileSize = 1024 * 15;
        var upload = false;

        using var content = new MultipartFormDataContent();

        foreach (var file in e.GetMultipleFiles(maxAllowedFiles))
        {
            if (uploadResults.SingleOrDefault(
                f => f.FileName == file.Name) is null)
            {
                try
                {
                    files.Add(new() { Name = file.Name });

                    var fileContent = new StreamContent(file.OpenReadStream(maxFileSize));

                    fileContent.Headers.ContentType = 
                        new MediaTypeHeaderValue(file.ContentType);

                    content.Add(
                        content: fileContent,
                        name: "\"files\"",
                        fileName: file.Name);

                    upload = true;
                }
                catch (Exception ex)
                {
                    Logger.LogInformation(
                        "{FileName} not uploaded (Err: 6): {Message}", 
                        file.Name, ex.Message);

                    uploadResults.Add(
                        new()
                        {
                            FileName = file.Name, 
                            ErrorCode = 6, 
                            Uploaded = false
                        });
                }
            }
        }

        if (upload)
        {
            var response = await Http.PostAsync("/Filesave", content);

            var newUploadResults = await response.Content
                .ReadFromJsonAsync<IList<UploadResult>>();

            if (newUploadResults is not null)
            {
                uploadResults = uploadResults.Concat(newUploadResults).ToList();
            }
        }

        shouldRender = true;
    }

    private static bool FileUpload(IList<UploadResult> uploadResults,
        string? fileName, ILogger<FileUpload2> logger, out UploadResult result)
    {
        result = uploadResults.SingleOrDefault(f => f.FileName == fileName) ?? new();

        if (!result.Uploaded)
        {
            logger.LogInformation("{FileName} not uploaded (Err: 5)", fileName);
            result.ErrorCode = 5;
        }

        return result.Uploaded;
    }

    private class File
    {
        public string? Name { get; set; }
    }
}

@page "/file-upload-2"
@using System.Linq
@using System.Net.Http.Headers
@using Microsoft.Extensions.Logging
@inject HttpClient Http
@inject ILogger<FileUpload2> Logger

<h1>Upload Files</h1>

<p>
    <label>
        Upload up to @maxAllowedFiles files:
        <InputFile OnChange="OnInputFileChange" multiple />
    </label>
</p>

@if (files.Count > 0)
{
    <div class="card">
        <div class="card-body">
            <ul>
                @foreach (var file in files)
                {
                    <li>
                        File: @file.Name
                        <br>
                        @if (FileUpload(uploadResults, file.Name, Logger,
                           out var result))
                        {
                            <span>
                                Stored File Name: @result.StoredFileName
                            </span>
                        }
                        else
                        {
                            <span>
                                There was an error uploading the file
                                (Error: @result.ErrorCode).
                            </span>
                        }
                    </li>
                }
            </ul>
        </div>
    </div>
}

@code {
    private List<File> files = new();
    private List<UploadResult> uploadResults = new();
    private int maxAllowedFiles = 3;
    private bool shouldRender;

    protected override bool ShouldRender() => shouldRender;

    private async Task OnInputFileChange(InputFileChangeEventArgs e)
    {
        shouldRender = false;
        long maxFileSize = 1024 * 15;
        var upload = false;

        using var content = new MultipartFormDataContent();

        foreach (var file in e.GetMultipleFiles(maxAllowedFiles))
        {
            if (uploadResults.SingleOrDefault(
                f => f.FileName == file.Name) is null)
            {
                try
                {
                    files.Add(new() { Name = file.Name });

                    var fileContent = new StreamContent(file.OpenReadStream(maxFileSize));

                    fileContent.Headers.ContentType = 
                        new MediaTypeHeaderValue(file.ContentType);

                    content.Add(
                        content: fileContent,
                        name: "\"files\"",
                        fileName: file.Name);

                    upload = true;
                }
                catch (Exception ex)
                {
                    Logger.LogInformation(
                        "{FileName} not uploaded (Err: 6): {Message}", 
                        file.Name, ex.Message);

                    uploadResults.Add(
                        new()
                        {
                            FileName = file.Name, 
                            ErrorCode = 6, 
                            Uploaded = false
                        });
                }
            }
        }

        if (upload)
        {
            var response = await Http.PostAsync("/Filesave", content);

            var newUploadResults = await response.Content
                .ReadFromJsonAsync<IList<UploadResult>>();

            if (newUploadResults is not null)
            {
                uploadResults = uploadResults.Concat(newUploadResults).ToList();
            }
        }

        shouldRender = true;
    }

    private static bool FileUpload(IList<UploadResult> uploadResults,
        string? fileName, ILogger<FileUpload2> logger, out UploadResult result)
    {
        result = uploadResults.SingleOrDefault(f => f.FileName == fileName) ?? new();

        if (!result.Uploaded)
        {
            logger.LogInformation("{FileName} not uploaded (Err: 5)", fileName);
            result.ErrorCode = 5;
        }

        return result.Uploaded;
    }

    private class File
    {
        public string? Name { get; set; }
    }
}

@page "/file-upload-2"
@using System.Linq
@using System.Net.Http.Headers
@using Microsoft.Extensions.Logging
@inject HttpClient Http
@inject ILogger<FileUpload2> Logger

<h1>Upload Files</h1>

<p>
    <label>
        Upload up to @maxAllowedFiles files:
        <InputFile OnChange="OnInputFileChange" multiple />
    </label>
</p>

@if (files.Count > 0)
{
    <div class="card">
        <div class="card-body">
            <ul>
                @foreach (var file in files)
                {
                    <li>
                        File: @file.Name
                        <br>
                        @if (FileUpload(uploadResults, file.Name, Logger,
                           out var result))
                        {
                            <span>
                                Stored File Name: @result.StoredFileName
                            </span>
                        }
                        else
                        {
                            <span>
                                There was an error uploading the file
                                (Error: @result.ErrorCode).
                            </span>
                        }
                    </li>
                }
            </ul>
        </div>
    </div>
}

@code {
    private List<File> files = new();
    private List<UploadResult> uploadResults = new();
    private int maxAllowedFiles = 3;
    private bool shouldRender;

    protected override bool ShouldRender() => shouldRender;

    private async Task OnInputFileChange(InputFileChangeEventArgs e)
    {
        shouldRender = false;
        long maxFileSize = 1024 * 15;
        var upload = false;

        using var content = new MultipartFormDataContent();

        foreach (var file in e.GetMultipleFiles(maxAllowedFiles))
        {
            if (uploadResults.SingleOrDefault(
                f => f.FileName == file.Name) is null)
            {
                try
                {
                    files.Add(new() { Name = file.Name });

                    var fileContent = new StreamContent(file.OpenReadStream(maxFileSize));

                    fileContent.Headers.ContentType = 
                        new MediaTypeHeaderValue(file.ContentType);

                    content.Add(
                        content: fileContent,
                        name: "\"files\"",
                        fileName: file.Name);

                    upload = true;
                }
                catch (Exception ex)
                {
                    Logger.LogInformation(
                        "{FileName} not uploaded (Err: 6): {Message}", 
                        file.Name, ex.Message);

                    uploadResults.Add(
                        new()
                        {
                            FileName = file.Name, 
                            ErrorCode = 6, 
                            Uploaded = false
                        });
                }
            }
        }

        if (upload)
        {
            var response = await Http.PostAsync("/Filesave", content);

            var newUploadResults = await response.Content
                .ReadFromJsonAsync<IList<UploadResult>>();

            uploadResults = uploadResults.Concat(newUploadResults).ToList();
        }

        shouldRender = true;
    }

    private static bool FileUpload(IList<UploadResult> uploadResults,
        string fileName, ILogger<FileUpload2> logger, out UploadResult result)
    {
        result = uploadResults.SingleOrDefault(f => f.FileName == fileName);

        if (result is null)
        {
            logger.LogInformation("{FileName} not uploaded (Err: 5)", fileName);
            result = new();
            result.ErrorCode = 5;
        }

        return result.Uploaded;
    }

    private class File
    {
        public string Name { get; set; }
    }
}

@page "/file-upload-3"
@inject ILogger<FileUpload3> Logger
@inject IWebHostEnvironment Environment

<PageTitle>File Upload 3</PageTitle>

<h1>File Upload Example 3</h1>

<p>
    <label>
        Max file size:
        <input type="number" @bind="maxFileSize" />
    </label>
</p>

<p>
    <label>
        Max allowed files:
        <input type="number" @bind="maxAllowedFiles" />
    </label>
</p>

<p>
    <label>
        Upload up to @maxAllowedFiles of up to @maxFileSize bytes:
        <InputFile OnChange="LoadFiles" multiple />
    </label>
</p>

@if (isLoading)
{
    <p>Progress: @string.Format("{0:P0}", progressPercent)</p>
}
else
{
    <ul>
        @foreach (var file in loadedFiles)
        {
            <li>
                <ul>
                    <li>Name: @file.Name</li>
                    <li>Last modified: @file.LastModified.ToString()</li>
                    <li>Size (bytes): @file.Size</li>
                    <li>Content type: @file.ContentType</li>
                </ul>
            </li>
        }
    </ul>
}

@code {
    private List<IBrowserFile> loadedFiles = new();
    private long maxFileSize = 1024 * 15;
    private int maxAllowedFiles = 3;
    private bool isLoading;
    private decimal progressPercent;

    private async Task LoadFiles(InputFileChangeEventArgs e)
    {
        isLoading = true;
        loadedFiles.Clear();
        progressPercent = 0;

        foreach (var file in e.GetMultipleFiles(maxAllowedFiles))
        {
            try
            {
                var trustedFileName = Path.GetRandomFileName();
                var path = Path.Combine(Environment.ContentRootPath,
                    Environment.EnvironmentName, "unsafe_uploads", trustedFileName);

                await using FileStream writeStream = new(path, FileMode.Create);
                using var readStream = file.OpenReadStream(maxFileSize);
                var bytesRead = 0;
                var totalRead = 0;
                var buffer = new byte[1024 * 10];

                while ((bytesRead = await readStream.ReadAsync(buffer)) != 0)
                {
                    totalRead += bytesRead;
                    await writeStream.WriteAsync(buffer, 0, bytesRead);
                    progressPercent = Decimal.Divide(totalRead, file.Size);
                    StateHasChanged();
                }

                loadedFiles.Add(file);

                Logger.LogInformation(
                    "Unsafe Filename: {UnsafeFilename} File saved: {Filename}",
                    file.Name, trustedFileName);
            }
            catch (Exception ex)
            {
                Logger.LogError("File: {FileName} Error: {Error}", 
                    file.Name, ex.Message);
            }
        }

        isLoading = false;
    }
}

@page "/file-upload-3"
@using System 
@using System.IO
@using Microsoft.AspNetCore.Hosting
@using Microsoft.Extensions.Logging
@inject ILogger<FileUpload3> Logger
@inject IWebHostEnvironment Environment

<h3>Upload Files</h3>

<p>
    <label>
        Max file size:
        <input type="number" @bind="maxFileSize" />
    </label>
</p>

<p>
    <label>
        Max allowed files:
        <input type="number" @bind="maxAllowedFiles" />
    </label>
</p>

<p>
    <label>
        Upload up to @maxAllowedFiles of up to @maxFileSize bytes:
        <InputFile OnChange="LoadFiles" multiple />
    </label>
</p>

@if (isLoading)
{
    <p>Progress: @string.Format("{0:P0}", progressPercent)</p>
}
else
{
    <ul>
        @foreach (var file in loadedFiles)
        {
            <li>
                <ul>
                    <li>Name: @file.Name</li>
                    <li>Last modified: @file.LastModified.ToString()</li>
                    <li>Size (bytes): @file.Size</li>
                    <li>Content type: @file.ContentType</li>
                </ul>
            </li>
        }
    </ul>
}

@code {
    private List<IBrowserFile> loadedFiles = new();
    private long maxFileSize = 1024 * 15;
    private int maxAllowedFiles = 3;
    private bool isLoading;
    private decimal progressPercent;

    private async Task LoadFiles(InputFileChangeEventArgs e)
    {
        isLoading = true;
        loadedFiles.Clear();
        progressPercent = 0;

        foreach (var file in e.GetMultipleFiles(maxAllowedFiles))
        {
            try
            {
                var trustedFileName = Path.GetRandomFileName();
                var path = Path.Combine(Environment.ContentRootPath,
                    Environment.EnvironmentName, "unsafe_uploads", trustedFileName);

                await using FileStream writeStream = new(path, FileMode.Create);
                using var readStream = file.OpenReadStream(maxFileSize);
                var bytesRead = 0;
                var totalRead = 0;
                var buffer = new byte[1024 * 10];

                while ((bytesRead = await readStream.ReadAsync(buffer)) != 0)
                {
                    totalRead += bytesRead;

                    await writeStream.WriteAsync(buffer, 0, bytesRead);

                    progressPercent = Decimal.Divide(totalRead, file.Size);

                    StateHasChanged();
                }

                loadedFiles.Add(file);
            }
            catch (Exception ex)
            {
                Logger.LogError("File: {FileName} Error: {Error}", 
                    file.Name, ex.Message);
            }
        }

        isLoading = false;
    }
}

@page "/file-upload-3"
@using System 
@using System.IO
@using Microsoft.AspNetCore.Hosting
@using Microsoft.Extensions.Logging
@inject ILogger<FileUpload3> Logger
@inject IWebHostEnvironment Environment

<h3>Upload Files</h3>

<p>
    <label>
        Max file size:
        <input type="number" @bind="maxFileSize" />
    </label>
</p>

<p>
    <label>
        Max allowed files:
        <input type="number" @bind="maxAllowedFiles" />
    </label>
</p>

<p>
    <label>
        Upload up to @maxAllowedFiles of up to @maxFileSize bytes:
        <InputFile OnChange="LoadFiles" multiple />
    </label>
</p>

@if (isLoading)
{
    <p>Progress: @string.Format("{0:P0}", progressPercent)</p>
}
else
{
    <ul>
        @foreach (var file in loadedFiles)
        {
            <li>
                <ul>
                    <li>Name: @file.Name</li>
                    <li>Last modified: @file.LastModified.ToString()</li>
                    <li>Size (bytes): @file.Size</li>
                    <li>Content type: @file.ContentType</li>
                </ul>
            </li>
        }
    </ul>
}

@code {
    private List<IBrowserFile> loadedFiles = new();
    private long maxFileSize = 1024 * 15;
    private int maxAllowedFiles = 3;
    private bool isLoading;
    private decimal progressPercent;

    private async Task LoadFiles(InputFileChangeEventArgs e)
    {
        isLoading = true;
        loadedFiles.Clear();
        progressPercent = 0;

        foreach (var file in e.GetMultipleFiles(maxAllowedFiles))
        {
            try
            {
                var trustedFileName = Path.GetRandomFileName();
                var path = Path.Combine(Environment.ContentRootPath,
                    Environment.EnvironmentName, "unsafe_uploads", trustedFileName);

                await using FileStream writeStream = new(path, FileMode.Create);
                using var readStream = file.OpenReadStream(maxFileSize);
                var bytesRead = 0;
                var totalRead = 0;
                var buffer = new byte[1024 * 10];

                while ((bytesRead = await readStream.ReadAsync(buffer)) != 0)
                {
                    totalRead += bytesRead;

                    await writeStream.WriteAsync(buffer, 0, bytesRead);

                    progressPercent = Decimal.Divide(totalRead, file.Size);

                    StateHasChanged();
                }

                loadedFiles.Add(file);
            }
            catch (Exception ex)
            {
                Logger.LogError("File: {Filename} Error: {Error}", 
                    file.Name, ex.Message);
            }
        }

        isLoading = false;
    }
}

@page "/file-upload-3"
@using System 
@using System.IO
@using Microsoft.AspNetCore.Hosting
@using Microsoft.Extensions.Logging
@inject ILogger<FileUpload3> Logger
@inject IWebHostEnvironment Environment

<h3>Upload Files</h3>

<p>
    <label>
        Max file size:
        <input type="number" @bind="maxFileSize" />
    </label>
</p>

<p>
    <label>
        Max allowed files:
        <input type="number" @bind="maxAllowedFiles" />
    </label>
</p>

<p>
    <label>
        Upload up to @maxAllowedFiles of up to @maxFileSize bytes:
        <InputFile OnChange="LoadFiles" multiple />
    </label>
</p>

@if (isLoading)
{
    <p>Progress: @string.Format("{0:P0}", progressPercent)</p>
}
else
{
    <ul>
        @foreach (var file in loadedFiles)
        {
            <li>
                <ul>
                    <li>Name: @file.Name</li>
                    <li>Last modified: @file.LastModified.ToString()</li>
                    <li>Size (bytes): @file.Size</li>
                    <li>Content type: @file.ContentType</li>
                </ul>
            </li>
        }
    </ul>
}

@code {
    private List<IBrowserFile> loadedFiles = new();
    private long maxFileSize = 1024 * 15;
    private int maxAllowedFiles = 3;
    private bool isLoading;
    private decimal progressPercent;

    private async Task LoadFiles(InputFileChangeEventArgs e)
    {
        isLoading = true;
        loadedFiles.Clear();
        progressPercent = 0;

        foreach (var file in e.GetMultipleFiles(maxAllowedFiles))
        {
            try
            {
                var trustedFileName = Path.GetRandomFileName();
                var path = Path.Combine(Environment.ContentRootPath,
                    Environment.EnvironmentName, "unsafe_uploads", trustedFileName);

                await using FileStream writeStream = new(path, FileMode.Create);
                using var readStream = file.OpenReadStream(maxFileSize);
                var bytesRead = 0;
                var totalRead = 0;
                var buffer = new byte[1024 * 10];

                while ((bytesRead = await readStream.ReadAsync(buffer)) != 0)
                {
                    totalRead += bytesRead;

                    await writeStream.WriteAsync(buffer, 0, bytesRead);

                    progressPercent = Decimal.Divide(totalRead, file.Size);

                    StateHasChanged();
                }

                loadedFiles.Add(file);
            }
            catch (Exception ex)
            {
                Logger.LogError("File: {Filename} Error: {Error}", 
                    file.Name, ex.Message);
            }
        }

        isLoading = false;
    }
}

RemoteBrowserFileStreamOptions permet de configurer les caractéristiques du chargement de fichiers.

Charger un aperçu des images

Pour obtenir un aperçu des images en cours de chargement, commencez par ajouter un composant InputFile avec une référence de composant et un gestionnaire OnChange :

<InputFile @ref="inputFile" OnChange="ShowPreview" />

Ajoutez un élément image avec une référence d’élément, qui sert d’espace réservé pour l’aperçu de l’image :

<img @ref="previewImageElem" />

Ajoutez les références associées :

@code {
    private InputFile? inputFile;
    private ElementReference previewImageElem;
}

En JavaScript, ajoutez une fonction appelée avec un input HTML et un élément img qui effectue les opérations suivantes :

• Extraction du fichier sélectionné.
• Création d’une URL d’objet avec createObjectURL.
• Définition d’un écouteur d’événements pour révoquer l’URL d’objet avec revokeObjectURL une fois l’image chargée, de façon à éviter une fuite de mémoire.
• Définition de la source de l’élément img pour afficher l’image.

window.previewImage = (inputElem, imgElem) => {
  const url = URL.createObjectURL(inputElem.files[0]);
  imgElem.addEventListener('load', () => URL.revokeObjectURL(url), { once: true });
  imgElem.src = url;
}

Enfin, utilisez un IJSRuntime injecté pour ajouter le gestionnaire OnChange qui appelle la fonction JavaScript :

@inject IJSRuntime JS

...

@code {
    ...

    private async Task ShowPreview() => await JS.InvokeVoidAsync(
        "previewImage", inputFile!.Element, previewImageElem);
}

L’exemple précédent concerne le chargement d’une seule image. L’approche peut être étendue afin de prendre en charge plusieurs (multiple) images.

Le composant FileUpload4 ci-dessous montre l’exemple complet.

FileUpload4.razor :

@page "/file-upload-4"
@inject IJSRuntime JS

<h1>File Upload Example</h1>

<InputFile @ref="inputFile" OnChange="ShowPreview" />

<img style="max-width:200px;max-height:200px" @ref="previewImageElem" />

@code {
    private InputFile? inputFile;
    private ElementReference previewImageElem;

    private async Task ShowPreview() => await JS.InvokeVoidAsync(
        "previewImage", inputFile!.Element, previewImageElem);
}

@page "/file-upload-4"
@inject IJSRuntime JS

<h1>File Upload Example</h1>

<InputFile @ref="inputFile" OnChange="ShowPreview" />

<img style="max-width:200px;max-height:200px" @ref="previewImageElem" />

@code {
    private InputFile? inputFile;
    private ElementReference previewImageElem;

    private async Task ShowPreview() => await JS.InvokeVoidAsync(
        "previewImage", inputFile!.Element, previewImageElem);
}

• Téléchargements de fichiers dans ASP.NET Core Blazor
• Charger des fichiers dans ASP.NET Core
• Vue d’ensemble des formulaires Blazor ASP.NET Core
• Dépôt GitHub d’exemples Blazor (dotnet/blazor-samples) (Comment télécharger)

• Charger des fichiers dans ASP.NET Core
• Vue d’ensemble des formulaires Blazor ASP.NET Core
• Dépôt GitHub d’exemples Blazor (dotnet/blazor-samples) (Comment télécharger)