MetadataBuilder Classe

Définition

public ref class MetadataBuilder sealed

public sealed class MetadataBuilder

type MetadataBuilder = class

Public NotInheritable Class MetadataBuilder

Héritage

Object

MetadataBuilder

Exemples

Cet exemple montre comment émettre un assembly d’application console à l’aide de MetadataBuilder:

private static readonly Guid s_guid = new Guid("87D4DBE1-1143-4FAD-AAB3-1001F92068E6");
private static readonly BlobContentId s_contentId = new BlobContentId(s_guid, 0x04030201);

private static MethodDefinitionHandle EmitHelloWorld(MetadataBuilder metadata, BlobBuilder ilBuilder)
{
    // Create module and assembly for a console application.
    metadata.AddModule(
        0,
        metadata.GetOrAddString("ConsoleApplication.exe"),
        metadata.GetOrAddGuid(s_guid),
        default(GuidHandle),
        default(GuidHandle));

    metadata.AddAssembly(
        metadata.GetOrAddString("ConsoleApplication"),
        version: new Version(1, 0, 0, 0),
        culture: default(StringHandle),
        publicKey: default(BlobHandle),
        flags: 0,
        hashAlgorithm: AssemblyHashAlgorithm.None);

    // Create references to System.Object and System.Console types.
    AssemblyReferenceHandle mscorlibAssemblyRef = metadata.AddAssemblyReference(
        name: metadata.GetOrAddString("mscorlib"),
        version: new Version(4, 0, 0, 0),
        culture: default(StringHandle),
        publicKeyOrToken: metadata.GetOrAddBlob(
            new byte[] { 0xB7, 0x7A, 0x5C, 0x56, 0x19, 0x34, 0xE0, 0x89 }
            ),
        flags: default(AssemblyFlags),
        hashValue: default(BlobHandle));

    TypeReferenceHandle systemObjectTypeRef = metadata.AddTypeReference(
        mscorlibAssemblyRef,
        metadata.GetOrAddString("System"),
        metadata.GetOrAddString("Object"));

    TypeReferenceHandle systemConsoleTypeRefHandle = metadata.AddTypeReference(
        mscorlibAssemblyRef,
        metadata.GetOrAddString("System"),
        metadata.GetOrAddString("Console"));

    // Get reference to Console.WriteLine(string) method.
    var consoleWriteLineSignature = new BlobBuilder();

    new BlobEncoder(consoleWriteLineSignature).
        MethodSignature().
        Parameters(1,
            returnType => returnType.Void(),
            parameters => parameters.AddParameter().Type().String());

    MemberReferenceHandle consoleWriteLineMemberRef = metadata.AddMemberReference(
        systemConsoleTypeRefHandle,
        metadata.GetOrAddString("WriteLine"),
        metadata.GetOrAddBlob(consoleWriteLineSignature));

    // Get reference to Object's constructor.
    var parameterlessCtorSignature = new BlobBuilder();

    new BlobEncoder(parameterlessCtorSignature).
        MethodSignature(isInstanceMethod: true).
        Parameters(0, returnType => returnType.Void(), parameters => { });

    BlobHandle parameterlessCtorBlobIndex = metadata.GetOrAddBlob(parameterlessCtorSignature);

    MemberReferenceHandle objectCtorMemberRef = metadata.AddMemberReference(
        systemObjectTypeRef,
        metadata.GetOrAddString(".ctor"),
        parameterlessCtorBlobIndex);

    // Create signature for "void Main()" method.
    var mainSignature = new BlobBuilder();

    new BlobEncoder(mainSignature).
        MethodSignature().
        Parameters(0, returnType => returnType.Void(), parameters => { });

    var methodBodyStream = new MethodBodyStreamEncoder(ilBuilder);

    var codeBuilder = new BlobBuilder();
    InstructionEncoder il;
    
    // Emit IL for Program::.ctor
    il = new InstructionEncoder(codeBuilder);

    // ldarg.0
    il.LoadArgument(0); 

    // call instance void [mscorlib]System.Object::.ctor()
    il.Call(objectCtorMemberRef);

    // ret
    il.OpCode(ILOpCode.Ret);

    int ctorBodyOffset = methodBodyStream.AddMethodBody(il);
    codeBuilder.Clear();

    // Emit IL for Program::Main
    var flowBuilder = new ControlFlowBuilder();
    il = new InstructionEncoder(codeBuilder, flowBuilder);

    // ldstr "hello"
    il.LoadString(metadata.GetOrAddUserString("Hello, world"));

    // call void [mscorlib]System.Console::WriteLine(string)
    il.Call(consoleWriteLineMemberRef);

    // ret
    il.OpCode(ILOpCode.Ret);

    int mainBodyOffset = methodBodyStream.AddMethodBody(il);
    codeBuilder.Clear();

    // Create method definition for Program::Main
    MethodDefinitionHandle mainMethodDef = metadata.AddMethodDefinition(
        MethodAttributes.Public | MethodAttributes.Static | MethodAttributes.HideBySig,
        MethodImplAttributes.IL,
        metadata.GetOrAddString("Main"),
        metadata.GetOrAddBlob(mainSignature),
        mainBodyOffset,
        parameterList: default(ParameterHandle));

    // Create method definition for Program::.ctor
    MethodDefinitionHandle ctorDef = metadata.AddMethodDefinition(
        MethodAttributes.Public | MethodAttributes.HideBySig | MethodAttributes.SpecialName | MethodAttributes.RTSpecialName,
        MethodImplAttributes.IL,
        metadata.GetOrAddString(".ctor"),
        parameterlessCtorBlobIndex,
        ctorBodyOffset,
        parameterList: default(ParameterHandle));

    // Create type definition for the special <Module> type that holds global functions
    metadata.AddTypeDefinition(
        default(TypeAttributes),
        default(StringHandle),
        metadata.GetOrAddString("<Module>"),
        baseType: default(EntityHandle),
        fieldList: MetadataTokens.FieldDefinitionHandle(1),
        methodList: mainMethodDef);

    // Create type definition for ConsoleApplication.Program
    metadata.AddTypeDefinition(
        TypeAttributes.Class | TypeAttributes.Public | TypeAttributes.AutoLayout | TypeAttributes.BeforeFieldInit,
        metadata.GetOrAddString("ConsoleApplication"),
        metadata.GetOrAddString("Program"),
        baseType: systemObjectTypeRef,
        fieldList: MetadataTokens.FieldDefinitionHandle(1),
        methodList: mainMethodDef);
    
    return mainMethodDef;
}

private static void WritePEImage(
    Stream peStream,
    MetadataBuilder metadataBuilder,
    BlobBuilder ilBuilder,
    MethodDefinitionHandle entryPointHandle
    )
{
    // Create executable with the managed metadata from the specified MetadataBuilder.
    var peHeaderBuilder = new PEHeaderBuilder(
        imageCharacteristics: Characteristics.ExecutableImage
        );

    var peBuilder = new ManagedPEBuilder(
        peHeaderBuilder,
        new MetadataRootBuilder(metadataBuilder),
        ilBuilder,
        entryPoint: entryPointHandle,
        flags: CorFlags.ILOnly,
        deterministicIdProvider: content => s_contentId);

    // Write executable into the specified stream.
    var peBlob = new BlobBuilder();
    BlobContentId contentId = peBuilder.Serialize(peBlob);
    peBlob.WriteContentTo(peStream);
}

public static void BuildHelloWorldApp()
{
    using var peStream = new FileStream(
        "ConsoleApplication.exe", FileMode.OpenOrCreate, FileAccess.ReadWrite
        );
    
    var ilBuilder = new BlobBuilder();
    var metadataBuilder = new MetadataBuilder();

    MethodDefinitionHandle entryPoint = EmitHelloWorld(metadataBuilder, ilBuilder);
    WritePEImage(peStream, metadataBuilder, ilBuilder, entryPoint);
}

Remarques

La MetadataBuilder classe vous permet de générer des assemblys par programmation. Ces assemblys peuvent être enregistrés dans un fichier, contrairement aux assemblys dynamiques générés par AssemblyBuilder la classe, qui ne prend pas en charge l’enregistrement des assemblys dans un fichier sur .NET 5+ et .NET Core.

L’API MetadataBuilder exploite des constructions de métadonnées de bas niveau, telles que des tables ou des objets blob. Pour obtenir un moyen plus simple de générer des assemblys dynamiquement à l’aide de C#, consultez CSharpCompilation API Roslyn.

Le format des métadonnées CLI est défini par la spécification ECMA-335. Pour plus d’informations, consultez Standard ECMA-335 - Common Language Infrastructure (CLI) sur le site Web Ecma International.

Constructeurs

Méthodes

S’applique à