FileUpload.FileBytes 屬性
定義
重要
部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。
取得使用 FileUpload 控制項指定之檔案中的位元組陣列。
public:
property cli::array <System::Byte> ^ FileBytes { cli::array <System::Byte> ^ get(); };[System.ComponentModel.Bindable(true)]
[System.ComponentModel.Browsable(false)]
public byte[] FileBytes { get; }[<System.ComponentModel.Bindable(true)>]
[<System.ComponentModel.Browsable(false)>]
member this.FileBytes : byte[]Public ReadOnly Property FileBytes As Byte()屬性值
- Byte[]
Byte 陣列，包含指定之檔案的內容。
- 屬性
例外狀況
未讀取整個檔案。
範例
下列範例示範如何建立 FileUpload 控制項。 當使用者按一下 [Upload檔案] 按鈕時，檔案的內容會顯示為頁面上文字方塊中的位元組。 這個範例會 FileBytes 使用 屬性來上傳整個檔案。
<%@ Page Language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>FileUpload.FileContent Property Example</title>
<script runat="server">
private void DisplayFileContents(HttpPostedFile file)
{
int fileLen;
string displayString = "";
// Get the length of the file.
fileLen = FileUpload1.PostedFile.ContentLength;
// Display the length of the file in a label.
LengthLabel.Text = "The length of the file is "
+ fileLen.ToString() + " bytes.";
// Create a byte array to hold the contents of the file.
byte[] input = new byte[fileLen - 1];
input = FileUpload1.FileBytes;
// Copy the byte array to a string.
for (int loop1 = 0; loop1 < fileLen; loop1++) {
displayString = displayString + input[loop1].ToString();
}
// Display the contents of the file in a
// textbox on the page.
ContentsLabel.Text = "The contents of the file as bytes:";
TextBox ContentsTextBox = new TextBox();
ContentsTextBox.TextMode = TextBoxMode.MultiLine;
ContentsTextBox.Height = Unit.Pixel(300);
ContentsTextBox.Width = Unit.Pixel(400);
ContentsTextBox.Text = displayString;
// Add the textbox to the Controls collection
// of the Placeholder control.
PlaceHolder1.Controls.Add(ContentsTextBox);
}
protected void UploadButton_Click(object sender, EventArgs e)
{
// Specify the path on the server to
// save the uploaded file to.
string savePath = @"c:\temp\uploads\";
// Before attempting to perform operations
// on the file, verify that the FileUpload
// control contains a file.
if (FileUpload1.HasFile) {
// Append the name of the file to upload to the path.
savePath += FileUpload1.FileName;
// Call the SaveAs method to save the
// uploaded file to the specified path.
// This example does not perform all
// the necessary error checking.
// If a file with the same name
// already exists in the specified path,
// the uploaded file overwrites it.
FileUpload1.SaveAs(savePath);
// Notify the user that the file was uploaded successfully.
UploadStatusLabel.Text = "Your file was uploaded successfully.";
// Call a helper routine to display the contents
// of the file to upload.
DisplayFileContents(FileUpload1.PostedFile);
}
else
{
// Notify the user that a file was not uploaded.
UploadStatusLabel.Text = "You did not specify a file to upload.";
}
}
</script>
</head>
<body>
<h3>FileUpload.FileContent Property Example</h3>
<form id="Form1" runat="server">
<h4>Select a file to upload:</h4>
<asp:FileUpload id="FileUpload1"
runat="server">
</asp:FileUpload>
<br /><br />
<asp:Button id="UploadButton"
Text="Upload file"
OnClick="UploadButton_Click"
runat="server">
</asp:Button>
<br /><br />
<asp:Label id="UploadStatusLabel"
runat="server">
</asp:Label>
<hr />
<asp:Label id="LengthLabel"
runat="server">
</asp:Label>
<br /><br />
<asp:Label id="ContentsLabel"
runat="server">
</asp:Label>
<br /><br />
<asp:PlaceHolder id="PlaceHolder1"
runat="server">
</asp:PlaceHolder>
</form>
</body>
</html>
<%@ Page Language="VB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>FileUpload.FileContent Property Example</title>
<script runat="server">
Sub UploadButton_Click(ByVal sender As Object, ByVal e As System.EventArgs)
' Specify the path on the server to
' save the uploaded file to.
Dim savePath As String = "c:\temp\uploads\"
' Before attempting to perform operations
' on the file, verify that the FileUpload
' control contains a file.
If (FileUpload1.HasFile) Then
' Append the name of the file to upload to the path.
savePath += FileUpload1.FileName
' Call the SaveAs method to save the
' uploaded file to the specified path.
' This example does not perform all
' the necessary error checking.
' If a file with the same name
' already exists in the specified path,
' the uploaded file overwrites it.
FileUpload1.SaveAs(savePath)
' Notify the user that the file was uploaded successfully.
UploadStatusLabel.Text = "Your file was uploaded successfully."
' Call a helper routine to display the contents
' of the file to upload.
DisplayFileContents(FileUpload1.PostedFile)
Else
' Notify the user that a file was not uploaded.
UploadStatusLabel.Text = "You did not specify a file to upload."
End If
End Sub
Sub DisplayFileContents(ByVal file As HttpPostedFile)
Dim fileLen As Integer
Dim displayString As String = ""
' Get the length of the file.
fileLen = FileUpload1.PostedFile.ContentLength
' Display the length of the file in a label.
LengthLabel.Text = "The length of the file is " _
& fileLen.ToString() & " bytes."
' Create a byte array to hold the contents of the file.
Dim Input(fileLen - 1) As Byte
Input = FileUpload1.FileBytes
' Copy the byte array to a string.
For loop1 As Integer = 0 To fileLen - 1
displayString = displayString & Input(loop1).ToString()
Next loop1
' Display the contents of the file in a
' textbox on the page.
ContentsLabel.Text = "The contents of the file as bytes:"
Dim ContentsTextBox As New TextBox
ContentsTextBox.TextMode = TextBoxMode.MultiLine
ContentsTextBox.Height = Unit.Pixel(300)
ContentsTextBox.Width = Unit.Pixel(400)
ContentsTextBox.Text = displayString
' Add the textbox to the Controls collection
' of the Placeholder control.
PlaceHolder1.Controls.Add(ContentsTextBox)
End Sub
</script>
</head>
<body>
<h3>FileUpload.FileContent Property Example</h3>
<form id="Form1" runat="server">
<h4>Select a file to upload:</h4>
<asp:FileUpload id="FileUpload1"
runat="server">
</asp:FileUpload>
<br /><br />
<asp:Button id="UploadButton"
Text="Upload file"
OnClick="UploadButton_Click"
runat="server">
</asp:Button>
<br /><br />
<asp:Label id="UploadStatusLabel"
runat="server">
</asp:Label>
<hr />
<asp:Label id="LengthLabel"
runat="server">
</asp:Label>
<br /><br />
<asp:Label id="ContentsLabel"
runat="server">
</asp:Label>
<br /><br />
<asp:PlaceHolder id="PlaceHolder1"
runat="server">
</asp:PlaceHolder>
</form>
</body>
</html>
備註
控制項 FileUpload 不會自動從用戶端讀取檔案。 您必須明確提供控制項或機制，讓使用者能夠提交指定的檔案。 例如，您可以提供使用者可以按一下以上傳檔案的按鈕。 您撰寫以儲存指定檔案的程式碼可以呼叫 FileBytes 屬性，這會傳回檔案的內容。
呼叫 FileBytes 屬性之前，您應該使用 HasFile 屬性來確認 FileUpload 控制項是否包含要上傳的檔案。 HasFile如果 傳回 true ，請呼叫 FileBytes 屬性。 如果傳回 false ，則會向使用者顯示訊息，指出控制項不包含檔案。 如果您未提供錯誤處理常式代碼來驗證檔案是否存在，則嘗試儲存不存在的檔案會 HttpException 擲回例外狀況。