MethodBuilder.MakeGenericMethod(Type[]) Method

Definition

Namespace:

System.Reflection.Emit

Assembly:

System.Reflection.Emit.dll

Returns a generic method constructed from the current generic method definition using the specified generic type arguments.

public:
 override System::Reflection::MethodInfo ^ MakeGenericMethod(... cli::array <Type ^> ^ typeArguments);

public override System.Reflection.MethodInfo MakeGenericMethod (params Type[] typeArguments);

override this.MakeGenericMethod : Type[] -> System.Reflection.MethodInfo

Public Overrides Function MakeGenericMethod (ParamArray typeArguments As Type()) As MethodInfo

Parameters

typeArguments

Type[]

An array of Type objects that represent the type arguments for the generic method.

Returns

MethodInfo

A MethodInfo representing the generic method constructed from the current generic method definition using the specified generic type arguments.

Examples

The following code example creates a constructed method from an incomplete generic method definition in an incomplete type.

The example creates a transient assembly and module with a single type, adds a method M, and makes the method generic by adding a type parameter T using the DefineGenericParameters method. The type parameter is used as the type of the method's parameter, and also as its return type. The generic method definition is not given a body, and the enclosing type is not completed. The MakeGenericMethod method is then used to make the constructed method M<String> (M(Of String) in Visual Basic). The example code has no output, because the subclass of MethodInfo returned by the MakeGenericMethod method does not allow reflection over its parameters.

Note

For another code example that uses MakeGenericMethod, see DefineGenericParameters. MakeGenericMethod is also used extensively when emitting code that uses generic types. See How to: Define a Generic Method with Reflection Emit.

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

void main()
{
    // Define a transient dynamic assembly (only to run, not
    // to save) with one module and a type "Test".
    // 
    AssemblyName^ aName = gcnew AssemblyName("MyDynamic");
    AssemblyBuilder^ ab = 
        AppDomain::CurrentDomain->DefineDynamicAssembly(
            aName, 
            AssemblyBuilderAccess::Run);
    ModuleBuilder^ mb = ab->DefineDynamicModule(aName->Name);
    TypeBuilder^ tb = mb->DefineType("Test");

    // Add a public static method "M" to Test, and make it a
    // generic method with one type parameter named "T").
    //
    MethodBuilder^ meb = tb->DefineMethod("M", 
        MethodAttributes::Public | MethodAttributes::Static);
    array<GenericTypeParameterBuilder^>^ typeParams = 
        meb->DefineGenericParameters(gcnew array<String^> { "T" });

    // Give the method one parameter, of type T, and a 
    // return type of T.
    meb->SetParameters(typeParams);
    meb->SetReturnType(typeParams[0]);

    // Create a MethodInfo for M<string>, which can be used in
    // emitted code. This is possible even though the method
    // does not yet have a body, and the enclosing type is not
    // created.
    MethodInfo^ mi = meb->MakeGenericMethod(String::typeid);
    // Note that this is actually a subclass of MethodInfo, 
    // which has rather limited capabilities -- for
    // example, you cannot reflect on its parameters.
}

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

class Example
{
    public static void Main()
    {
        // Define a transient dynamic assembly (only to run, not
        // to save) with one module and a type "Test".
        //
        AssemblyName aName = new AssemblyName("MyDynamic");
        AssemblyBuilder ab =
            AppDomain.CurrentDomain.DefineDynamicAssembly(
                aName,
                AssemblyBuilderAccess.Run);
        ModuleBuilder mb = ab.DefineDynamicModule(aName.Name);
        TypeBuilder tb = mb.DefineType("Test");

        // Add a public static method "M" to Test, and make it a
        // generic method with one type parameter named "T").
        //
        MethodBuilder meb = tb.DefineMethod("M",
            MethodAttributes.Public | MethodAttributes.Static);
        GenericTypeParameterBuilder[] typeParams =
            meb.DefineGenericParameters(new string[] { "T" });

        // Give the method one parameter, of type T, and a
        // return type of T.
        meb.SetParameters(typeParams);
        meb.SetReturnType(typeParams[0]);

        // Create a MethodInfo for M<string>, which can be used in
        // emitted code. This is possible even though the method
        // does not yet have a body, and the enclosing type is not
        // created.
        MethodInfo mi = meb.MakeGenericMethod(typeof(string));
        // Note that this is actually a subclass of MethodInfo,
        // which has rather limited capabilities -- for
        // example, you cannot reflect on its parameters.
    }
}

Imports System.Reflection
Imports System.Reflection.Emit

Class Example

    Public Shared Sub Main()
    
        ' Define a transient dynamic assembly (only to run, not
        ' to save) with one module and a type "Test".
        ' 
        Dim aName As AssemblyName = New AssemblyName("MyDynamic")
        Dim ab As AssemblyBuilder = _
            AppDomain.CurrentDomain.DefineDynamicAssembly( _
                aName, _
                AssemblyBuilderAccess.Run)
        Dim mb As ModuleBuilder = ab.DefineDynamicModule(aName.Name)
        Dim tb As TypeBuilder = mb.DefineType("Test")

        ' Add a Public Shared method "M" to Test, and make it a
        ' generic method with one type parameter named "T").
        '
        Dim meb As MethodBuilder = tb.DefineMethod("M", _
            MethodAttributes.Public Or MethodAttributes.Static)
        Dim typeParams() As GenericTypeParameterBuilder = _
            meb.DefineGenericParameters(New String() { "T" })

        ' Give the method one parameter, of type T, and a 
        ' return type of T.
        meb.SetParameters(typeParams)
        meb.SetReturnType(typeParams(0))

        ' Create a MethodInfo for M(Of String), which can be used 
        ' in emitted code. This is possible even though the method
        ' does not yet have a body, and the enclosing type is not
        ' created.
        Dim mi As MethodInfo = _
            meb.MakeGenericMethod(GetType(String))
        ' Note that this is actually a subclass of MethodInfo, 
        ' which has rather limited capabilities -- for
        ' example, you cannot reflect on its parameters.
    End Sub
End Class

Remarks

When you are emitting dynamic code, you might need to emit a call to a method constructed from the generic method definition represented by a MethodBuilder, before the enclosing type has been completed. You can use the MakeGenericMethod method to create a MethodInfo for such a constructed method, and use the MethodInfo in the emitted call.

See also

• How to: Define a Generic Method with Reflection Emit