MethodBuilder.DefineGenericParameters(String[]) Método

Definição

Namespace:

System.Reflection.Emit

Assembly:

System.Reflection.Emit.dll

Origem:

MethodBuilder.cs

Define o número de parâmetros de tipo genérico para o método atual, especifica seus nomes e retorna uma matriz de objetos GenericTypeParameterBuilder que pode ser usada para definir suas restrições.

public:
 cli::array <System::Reflection::Emit::GenericTypeParameterBuilder ^> ^ DefineGenericParameters(... cli::array <System::String ^> ^ names);

public System.Reflection.Emit.GenericTypeParameterBuilder[] DefineGenericParameters (params string[] names);

member this.DefineGenericParameters : string[] -> System.Reflection.Emit.GenericTypeParameterBuilder[]

Public Function DefineGenericParameters (ParamArray names As String()) As GenericTypeParameterBuilder()

Parâmetros

names

String[]

Uma matriz de cadeias de caracteres que representa os nomes dos parâmetros de tipo genérico.

Retornos

GenericTypeParameterBuilder[]

Uma matriz de objetos GenericTypeParameterBuilder que representam os parâmetros de tipo do método genérico.

Exceções

InvalidOperationException

Parâmetros de tipo genérico já foram definidos para este método.

- ou -

O método já foi concluído.

- ou -

O método SetImplementationFlags(MethodImplAttributes) foi chamado para o método atual.

ArgumentNullException

names é null.

- ou -

Um elemento de names é null.

ArgumentException

names é uma matriz vazia.

Exemplos

O exemplo de código a seguir cria um tipo dinâmico, DemoType, que contém o método DemoMethodgenérico dinâmico . Esse método tem dois parâmetros de tipo genérico, um dos quais é usado como um parâmetro e o outro como o tipo de retorno.

Quando o código é executado, o assembly dinâmico é salvo como DemoGenericMethod1.dll e pode ser examinado usando o Ildasm.exe (IL Disassembler).

Observação

Este exemplo de código gera um corpo de método simples que simplesmente retorna uma referência nula. Para obter um exemplo de código com um corpo de método mais totalmente desenvolvido que cria e usa tipos genéricos, consulte Como definir um método genérico com a emissão de reflexão.

using namespace System;
using namespace System::Reflection;
using namespace System::Reflection::Emit;

public ref class GenericReflectionSample
{
};

int main()
{
    // Creating a dynamic assembly requires an AssemblyName
    // object, and the current application domain.
    //
    AssemblyName^ asmName =
        gcnew AssemblyName("EmittedAssembly");
    AppDomain^ domain = AppDomain::CurrentDomain;
    AssemblyBuilder^ sampleAssemblyBuilder =
        domain->DefineDynamicAssembly(asmName,
        AssemblyBuilderAccess::RunAndSave);

    // Define the module that contains the code. For an
    // assembly with one module, the module name is the
    // assembly name plus a file extension.
    ModuleBuilder^ sampleModuleBuilder =
        sampleAssemblyBuilder->DefineDynamicModule(asmName->Name,
        asmName->Name + ".dll");

    TypeBuilder^ sampleTypeBuilder =
        sampleModuleBuilder->DefineType("SampleType",
        TypeAttributes::Public | TypeAttributes::Abstract);

    // Define a Shared, Public method with standard calling
    // conventions. Do not specify the parameter types or the
    // return type, because type parameters will be used for
    // those types, and the type parameters have not been
    // defined yet.
    MethodBuilder^ sampleMethodBuilder =
        sampleTypeBuilder->DefineMethod("SampleMethod",
        MethodAttributes::Public | MethodAttributes::Static);

    // Defining generic parameters for the method makes it a
    // generic method. By convention, type parameters are
    // single alphabetic characters. T and U are used here.
    //
    array<String^>^ genericTypeNames = {"T", "U"};
    array<GenericTypeParameterBuilder^>^ genericTypes =
        sampleMethodBuilder->DefineGenericParameters(
        genericTypeNames);

    // Use the IsGenericMethod property to find out if a
    // dynamic method is generic, and IsGenericMethodDefinition
    // to find out if it defines a generic method.
    Console::WriteLine("Is SampleMethod generic? {0}",
        sampleMethodBuilder->IsGenericMethod);
    Console::WriteLine(
        "Is SampleMethod a generic method definition? {0}",
        sampleMethodBuilder->IsGenericMethodDefinition);

    // Set parameter types for the method. The method takes
    // one parameter, and its type is specified by the first
    // type parameter, T.
    array<Type^>^ parameterTypes = {genericTypes[0]};
    sampleMethodBuilder->SetParameters(parameterTypes);

    // Set the return type for the method. The return type is
    // specified by the second type parameter, U.
    sampleMethodBuilder->SetReturnType(genericTypes[1]);

    // Generate a code body for the method. The method doesn't
    // do anything except return null.
    //
    ILGenerator^ ilgen = sampleMethodBuilder->GetILGenerator();
    ilgen->Emit(OpCodes::Ldnull);
    ilgen->Emit(OpCodes::Ret);

    // Complete the type.
    Type^ sampleType = sampleTypeBuilder->CreateType();

    // To bind types to a dynamic generic method, you must
    // first call the GetMethod method on the completed type.
    // You can then define an array of types, and bind them
    // to the method.
    MethodInfo^ sampleMethodInfo = sampleType->GetMethod("SampleMethod");
    array<Type^>^ boundParameters =
        {String::typeid, GenericReflectionSample::typeid};
    MethodInfo^ boundMethodInfo =
        sampleMethodInfo->MakeGenericMethod(boundParameters);
    // Display a string representing the bound method.
    Console::WriteLine(boundMethodInfo);

    // Save the assembly, so it can be examined with Ildasm.exe.
    sampleAssemblyBuilder->Save(asmName->Name + ".dll");
}

/* This code example produces the following output:
Is SampleMethod generic? True
Is SampleMethod a generic method definition? True
GenericReflectionSample SampleMethod[String,GenericReflectionSample](System.String)
*/

using System;
using System.Reflection;
using System.Reflection.Emit;

class DemoMethodBuilder
{

    public static void Main()
    {
        // Creating a dynamic assembly requires an AssemblyName
        // object, and the current application domain.
        //
        AssemblyName asmName =
            new AssemblyName("DemoMethodBuilder1");
        AppDomain domain = AppDomain.CurrentDomain;
        AssemblyBuilder demoAssembly =
            domain.DefineDynamicAssembly(
                asmName,
                AssemblyBuilderAccess.RunAndSave
            );

        // Define the module that contains the code. For an
        // assembly with one module, the module name is the
        // assembly name plus a file extension.
        ModuleBuilder demoModule =
            demoAssembly.DefineDynamicModule(
                asmName.Name,
                asmName.Name + ".dll"
            );

        TypeBuilder demoType = demoModule.DefineType(
            "DemoType",
            TypeAttributes.Public | TypeAttributes.Abstract
        );

        // Define a Shared, Public method with standard calling
        // conventions. Do not specify the parameter types or the
        // return type, because type parameters will be used for
        // those types, and the type parameters have not been
        // defined yet.
        MethodBuilder demoMethod = demoType.DefineMethod(
            "DemoMethod",
            MethodAttributes.Public | MethodAttributes.Static
        );

        // Defining generic parameters for the method makes it a
        // generic method. By convention, type parameters are
        // single alphabetic characters. T and U are used here.
        //
        string[] typeParamNames = {"T", "U"};
        GenericTypeParameterBuilder[] typeParameters =
            demoMethod.DefineGenericParameters(typeParamNames);

        // The second type parameter is constrained to be a
        // reference type.
        typeParameters[1].SetGenericParameterAttributes(
            GenericParameterAttributes.ReferenceTypeConstraint);

        // Use the IsGenericMethod property to find out if a
        // dynamic method is generic, and IsGenericMethodDefinition
        // to find out if it defines a generic method.
        Console.WriteLine("Is DemoMethod generic? {0}",
            demoMethod.IsGenericMethod);
        Console.WriteLine("Is DemoMethod a generic method definition? {0}",
            demoMethod.IsGenericMethodDefinition);

        // Set parameter types for the method. The method takes
        // one parameter, and its type is specified by the first
        // type parameter, T.
        Type[] parms = {typeParameters[0]};
        demoMethod.SetParameters(parms);

        // Set the return type for the method. The return type is
        // specified by the second type parameter, U.
        demoMethod.SetReturnType(typeParameters[1]);

        // Generate a code body for the method. The method doesn't
        // do anything except return null.
        //
        ILGenerator ilgen = demoMethod.GetILGenerator();
        ilgen.Emit(OpCodes.Ldnull);
        ilgen.Emit(OpCodes.Ret);

        // Complete the type.
        Type dt = demoType.CreateType();

        // To bind types to a dynamic generic method, you must
        // first call the GetMethod method on the completed type.
        // You can then define an array of types, and bind them
        // to the method.
        MethodInfo m = dt.GetMethod("DemoMethod");
        Type[] typeArgs = {typeof(string), typeof(DemoMethodBuilder)};
        MethodInfo bound = m.MakeGenericMethod(typeArgs);
        // Display a string representing the bound method.
        Console.WriteLine(bound);

        // Save the assembly, so it can be examined with Ildasm.exe.
        demoAssembly.Save(asmName.Name + ".dll");
    }
}

/* This code example produces the following output:
Is DemoMethod generic? True
Is DemoMethod a generic method definition? True
DemoMethodBuilder DemoMethod[String,DemoMethodBuilder](System.String)
*/

Imports System.Reflection
Imports System.Reflection.Emit

Class DemoMethodBuilder
   
    Public Shared Sub Main()
        ' Creating a dynamic assembly requires an AssemblyName
        ' object, and the current application domain.
        '
        Dim asmName As New AssemblyName("DemoMethodBuilder1")
        Dim domain As AppDomain = AppDomain.CurrentDomain
        Dim demoAssembly As AssemblyBuilder = _
            domain.DefineDynamicAssembly(asmName, _
                AssemblyBuilderAccess.RunAndSave)

        ' Define the module that contains the code. For an 
        ' assembly with one module, the module name is the 
        ' assembly name plus a file extension.
        Dim demoModule As ModuleBuilder = _
            demoAssembly.DefineDynamicModule( _
                asmName.Name, _
                asmName.Name & ".dll")
      
        Dim demoType As TypeBuilder = demoModule.DefineType( _
            "DemoType", _
            TypeAttributes.Public Or TypeAttributes.Abstract)

        ' Define a Shared, Public method with standard calling
        ' conventions. Do not specify the parameter types or the
        ' return type, because type parameters will be used for 
        ' those types, and the type parameters have not been
        ' defined yet.
        Dim demoMethod As MethodBuilder = _
            demoType.DefineMethod("DemoMethod", _
                MethodAttributes.Public Or MethodAttributes.Static)

        ' Defining generic parameters for the method makes it a
        ' generic method. By convention, type parameters are 
        ' single alphabetic characters. T and U are used here.
        '
        Dim typeParamNames() As String = {"T", "U"}
        Dim typeParameters() As GenericTypeParameterBuilder = _
            demoMethod.DefineGenericParameters(typeParamNames)

        ' The second type parameter is constrained to be a 
        ' reference type.
        typeParameters(1).SetGenericParameterAttributes( _
            GenericParameterAttributes.ReferenceTypeConstraint)

        ' Use the IsGenericMethod property to find out if a
        ' dynamic method is generic, and IsGenericMethodDefinition
        ' to find out if it defines a generic method.
        Console.WriteLine("Is DemoMethod generic? {0}", _
            demoMethod.IsGenericMethod)
        Console.WriteLine("Is DemoMethod a generic method definition? {0}", _
            demoMethod.IsGenericMethodDefinition)

        ' Set parameter types for the method. The method takes
        ' one parameter, and its type is specified by the first
        ' type parameter, T.
        Dim params() As Type = {typeParameters(0)}
        demoMethod.SetParameters(params)

        ' Set the return type for the method. The return type is
        ' specified by the second type parameter, U.
        demoMethod.SetReturnType(typeParameters(1))

        ' Generate a code body for the method. The method doesn't
        ' do anything except return Nothing.
        '
        Dim ilgen As ILGenerator = demoMethod.GetILGenerator()
        ilgen.Emit(OpCodes.Ldnull)
        ilgen.Emit(OpCodes.Ret)

        ' Complete the type.
        Dim dt As Type = demoType.CreateType()

        ' To bind types to a dynamic generic method, you must 
        ' first call the GetMethod method on the completed type.
        ' You can then define an array of types, and bind them
        ' to the method.
        Dim m As MethodInfo = dt.GetMethod("DemoMethod")
        Dim typeArgs() As Type = _
            {GetType(String), GetType(DemoMethodBuilder)}
        Dim bound As MethodInfo = m.MakeGenericMethod(typeArgs)
        ' Display a string representing the bound method.
        Console.WriteLine(bound)

        ' Save the assembly, so it can be examined with Ildasm.exe.
        demoAssembly.Save(asmName.Name & ".dll")
    End Sub  
End Class 

' This code example produces the following output:
'Is DemoMethod generic? True
'Is DemoMethod a generic method definition? True
'DemoMethodBuilder DemoMethod[String,DemoMethodBuilder](System.String)

Comentários

Chamar o DefineGenericParameters método torna o método atual genérico. Não há como desfazer essa alteração. Chamar esse método uma segunda vez causa um InvalidOperationException.

Os parâmetros de tipo do método genérico podem ser recuperados posteriormente usando o GetGenericArguments método .

Por convenção, um nome de parâmetro de tipo é uma única letra maiúscula.

Para obter mais informações, consulte MethodBase.IsGenericMethod e MethodInfo.GetGenericMethodDefinition. Para obter informações sobre tipos genéricos, consulte Type.IsGenericType.

Confira também

• MethodInfo
• IsGenericType
• DefineMethod
• Como: Definir um método genérico com a emissão de reflexão