MethodBuilder.DefineGenericParameters(String[]) Metoda

  • Odwołanie

Definicja

Przestrzeń nazw:
System.Reflection.Emit
Zestaw:
System.Reflection.Emit.dll
Zestaw:
mscorlib.dll
Zestaw:
netstandard.dll
Źródło:
MethodBuilder.cs
Źródło:
MethodBuilder.cs
Źródło:
MethodBuilder.cs

Ustawia liczbę parametrów typu ogólnego dla bieżącej metody, określa ich nazwy i zwraca tablicę GenericTypeParameterBuilder obiektów, których można użyć do zdefiniowania ich ograniczeń.

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()

Parametry

names
String[]

Tablica ciągów reprezentujących nazwy parametrów typu ogólnego.

Zwraca

GenericTypeParameterBuilder[]

Tablica GenericTypeParameterBuilder obiektów reprezentujących parametry typu metody ogólnej.

Wyjątki

InvalidOperationException

Parametry typu ogólnego zostały już zdefiniowane dla tej metody.

-lub-

Metoda została już ukończona.

-lub-

Metoda SetImplementationFlags(MethodImplAttributes) została wywołana dla bieżącej metody.

ArgumentNullException

names to null.

-lub-

Elementem elementu names jest null.

ArgumentException

names jest pustą tablicą.

Przykłady

Poniższy przykład kodu tworzy typ dynamiczny , DemoTypektóry zawiera dynamiczną metodę DemoMethodogólną . Ta metoda ma dwa ogólne parametry typu, z których jeden jest używany jako parametr, a drugi jako typ zwracany.

Po wykonaniu kodu zestaw dynamiczny jest zapisywany jako DemoGenericMethod1.dll i można go zbadać przy użyciu Ildasm.exe (IL Dezasembler).

Uwaga

Ten przykład kodu generuje prostą treść metody, która jedynie zwraca odwołanie o wartości null. Aby zapoznać się z przykładem kodu z bardziej w pełni opracowaną treścią metody, która tworzy typy ogólne i używa ich, zobacz How to: Define a Generic Method with Reflection Emit (Instrukcje: Definiowanie metody ogólnej z emitem odbicia).

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)

Uwagi

Wywołanie metody sprawia, że bieżąca DefineGenericParameters metoda jest ogólna. Nie ma możliwości cofnięcia tej zmiany. Wywołanie tej metody po raz drugi powoduje wywołanie metody InvalidOperationException.

Parametry typu metody ogólnej można pobrać później przy użyciu GetGenericArguments metody .

Zgodnie z konwencją nazwa parametru typu jest jedną wielką literą.

Aby uzyskać więcej informacji, zobacz MethodBase.IsGenericMethod i MethodInfo.GetGenericMethodDefinition. Aby uzyskać informacje na temat typów ogólnych, zobacz Type.IsGenericType.

Dotyczy

Zobacz też