TypeBuilder.DefineMethod Method

Definition

Namespace:

System.Reflection.Emit

Assemblies:

netstandard.dll, System.Reflection.Emit.dll

Adds a method to the type.

Overloads

DefineMethod(String, MethodAttributes, CallingConventions, Type, Type[], Type[], Type[], Type[][], Type[][])	Adds a new method to the type, with the specified name, method attributes, calling convention, method signature, and custom modifiers.
DefineMethod(String, MethodAttributes, CallingConventions, Type, Type[])	Adds a new method to the type, with the specified name, method attributes, calling convention, and method signature.
DefineMethod(String, MethodAttributes, CallingConventions)	Adds a new method to the type, with the specified name, method attributes, and calling convention.
DefineMethod(String, MethodAttributes)	Adds a new method to the type, with the specified name and method attributes.
DefineMethod(String, MethodAttributes, Type, Type[])	Adds a new method to the type, with the specified name, method attributes, and method signature.

DefineMethod(String, MethodAttributes, CallingConventions, Type, Type[], Type[], Type[], Type[][], Type[][])

Source:

TypeBuilder.cs

Adds a new method to the type, with the specified name, method attributes, calling convention, method signature, and custom modifiers.

C#

public System.Reflection.Emit.MethodBuilder DefineMethod(string name, System.Reflection.MethodAttributes attributes, System.Reflection.CallingConventions callingConvention, Type? returnType, Type[]? returnTypeRequiredCustomModifiers, Type[]? returnTypeOptionalCustomModifiers, Type[]? parameterTypes, Type[][]? parameterTypeRequiredCustomModifiers, Type[][]? parameterTypeOptionalCustomModifiers);

Parameters

name

String

The name of the method. name cannot contain embedded nulls.

attributes

MethodAttributes

The attributes of the method.

callingConvention

CallingConventions

The calling convention of the method.

returnType

Type

The return type of the method.

returnTypeRequiredCustomModifiers

Type[]

An array of types representing the required custom modifiers, such as IsConst, for the return type of the method. If the return type has no required custom modifiers, specify null.

returnTypeOptionalCustomModifiers

Type[]

An array of types representing the optional custom modifiers, such as IsConst, for the return type of the method. If the return type has no optional custom modifiers, specify null.

parameterTypes

Type[]

The types of the parameters of the method.

parameterTypeRequiredCustomModifiers

Type[][]

An array of arrays of types. Each array of types represents the required custom modifiers for the corresponding parameter, such as IsConst. If a particular parameter has no required custom modifiers, specify null instead of an array of types. If none of the parameters have required custom modifiers, specify null instead of an array of arrays.

parameterTypeOptionalCustomModifiers

Type[][]

An array of arrays of types. Each array of types represents the optional custom modifiers for the corresponding parameter, such as IsConst. If a particular parameter has no optional custom modifiers, specify null instead of an array of types. If none of the parameters have optional custom modifiers, specify null instead of an array of arrays.

Returns

MethodBuilder

A MethodBuilder object representing the newly added method.

Exceptions

ArgumentException

The length of name is zero.

-or-

The type of the parent of this method is an interface, and this method is not virtual (Overridable in Visual Basic).

-or-

The size of parameterTypeRequiredCustomModifiers or parameterTypeOptionalCustomModifiers does not equal the size of parameterTypes.

ArgumentNullException

name is null.

InvalidOperationException

The type was previously created using CreateType().

-or-

For the current dynamic type, the IsGenericType property is true, but the IsGenericTypeDefinition property is false.

Remarks

Use this overload if you need to specify custom modifiers. If you need to specify custom modifiers after the method has been created, as you would, for example, with a generic method whose parameter types are specified by its generic type parameters, you can use the DefineMethod(String, MethodAttributes) or DefineMethod(String, MethodAttributes, CallingConventions) method overloads to define the method and then use the MethodBuilder.SetSignature method to define the parameter and return types with custom modifiers.

Note

For more information on custom modifiers, see ECMA C# and Common Language Infrastructure Standards and Standard ECMA-335 - Common Language Infrastructure (CLI).

DefineMethod(String, MethodAttributes, CallingConventions, Type, Type[])

Source:

TypeBuilder.cs

Adds a new method to the type, with the specified name, method attributes, calling convention, and method signature.

C#

public System.Reflection.Emit.MethodBuilder DefineMethod(string name, System.Reflection.MethodAttributes attributes, System.Reflection.CallingConventions callingConvention, Type? returnType, Type[]? parameterTypes);

Parameters

name

String

The name of the method. name cannot contain embedded nulls.

attributes

MethodAttributes

The attributes of the method.

callingConvention

CallingConventions

The calling convention of the method.

returnType

Type

The return type of the method.

parameterTypes

Type[]

The types of the parameters of the method.

Returns

MethodBuilder

A MethodBuilder representing the newly defined method.

Exceptions

ArgumentException

The length of name is zero.

-or-

The type of the parent of this method is an interface, and this method is not virtual (Overridable in Visual Basic).

ArgumentNullException

name is null.

InvalidOperationException

The type was previously created using CreateType().

-or-

For the current dynamic type, the IsGenericType property is true, but the IsGenericTypeDefinition property is false.

Examples

The following code sample demonstrates the use of DefineMethod to set a constructor's particular signature and attributes on a dynamic type and to return a corresponding MethodBuilder for MSIL population.

C#

using System;
using System.Threading;
using System.Reflection;
using System.Reflection.Emit;
using System.Security.Permissions;

public interface IMyInterface
{
   String HelloMethod(String parameter);
}

public class Example
{
   public static void Main()
   {
      Type myNestedClassType = CreateCallee(Thread.GetDomain());
      // Cretae an instance of 'MyNestedClass'.
      IMyInterface myInterface =
         (IMyInterface)Activator.CreateInstance(myNestedClassType);
      Console.WriteLine(myInterface.HelloMethod("Bill"));
   }

   // Create the callee transient dynamic assembly.
   private static Type CreateCallee(AppDomain myAppDomain)
   {
      AssemblyName myAssemblyName = new AssemblyName();
      myAssemblyName.Name = "Example";
      // Create the callee dynamic assembly.
      AssemblyBuilder myAssembly =
         myAppDomain.DefineDynamicAssembly(myAssemblyName, AssemblyBuilderAccess.Run);
      // Create a dynamic module in the callee assembly.
      ModuleBuilder myModule = myAssembly.DefineDynamicModule("EmittedModule");
      // Define a public class named "MyHelloWorld".
      TypeBuilder myHelloWorldType =
         myModule.DefineType("MyHelloWorld", TypeAttributes.Public);
      // Define a public nested class named 'MyNestedClass'.
      TypeBuilder myNestedClassType =
         myHelloWorldType.DefineNestedType("MyNestedClass",
            TypeAttributes.NestedPublic, typeof(Example),
            new Type[]{typeof(IMyInterface)});
      // Implement 'IMyInterface' interface.
      myNestedClassType.AddInterfaceImplementation(typeof(IMyInterface));
      // Define 'HelloMethod' of 'IMyInterface'.
      MethodBuilder myHelloMethod =
         myNestedClassType.DefineMethod("HelloMethod",
            MethodAttributes.Public | MethodAttributes.Virtual,
            typeof(String), new Type[]{typeof(String)});
      // Generate IL for 'GetGreeting' method.
      ILGenerator myMethodIL = myHelloMethod.GetILGenerator();
      myMethodIL.Emit(OpCodes.Ldstr, "Hi! ");
      myMethodIL.Emit(OpCodes.Ldarg_1);
      MethodInfo infoMethod =
         typeof(String).GetMethod("Concat",new Type[]{typeof(string),typeof(string)});
      myMethodIL.Emit(OpCodes.Call, infoMethod);
      myMethodIL.Emit(OpCodes.Ret);

      MethodInfo myHelloMethodInfo =
         typeof(IMyInterface).GetMethod("HelloMethod");
      // Implement 'HelloMethod' of 'IMyInterface'.
      myNestedClassType.DefineMethodOverride(myHelloMethod, myHelloMethodInfo);
      // Create 'MyHelloWorld' type.
      Type myType = myHelloWorldType.CreateType();
      // Create 'MyNestedClass' type.
      return myNestedClassType.CreateType();
   }
}

DefineMethod(String, MethodAttributes, CallingConventions)

Source:

TypeBuilder.cs

Adds a new method to the type, with the specified name, method attributes, and calling convention.

C#

public System.Reflection.Emit.MethodBuilder DefineMethod(string name, System.Reflection.MethodAttributes attributes, System.Reflection.CallingConventions callingConvention);

Parameters

name

String

The name of the method. name cannot contain embedded nulls.

attributes

MethodAttributes

The attributes of the method.

callingConvention

CallingConventions

The calling convention of the method.

Returns

MethodBuilder

A MethodBuilder representing the newly defined method.

Exceptions

ArgumentException

The length of name is zero.

-or-

The type of the parent of this method is an interface and this method is not virtual (Overridable in Visual Basic).

ArgumentNullException

name is null.

InvalidOperationException

The type was previously created using CreateType().

-or-

For the current dynamic type, the IsGenericType property is true, but the IsGenericTypeDefinition property is false.

Remarks

Use this method overload when you do not know the method signature at the time you define the method. For example, the parameter types and return type of a generic method might be specified by the method's generic type parameters, which must be defined after the method has been added to the type. The parameters and return type of the method can be set later using the MethodBuilder.SetSignature method.

See also

• DefineGenericParameters(String[])

DefineMethod(String, MethodAttributes)

Source:

TypeBuilder.cs

Adds a new method to the type, with the specified name and method attributes.

C#

public System.Reflection.Emit.MethodBuilder DefineMethod(string name, System.Reflection.MethodAttributes attributes);

Parameters

name

String

The name of the method. name cannot contain embedded nulls.

attributes

MethodAttributes

The attributes of the method.

Returns

MethodBuilder

A MethodBuilder representing the newly defined method.

Exceptions

ArgumentException

The length of name is zero.

-or-

The type of the parent of this method is an interface, and this method is not virtual (Overridable in Visual Basic).

ArgumentNullException

name is null.

InvalidOperationException

The type was previously created using CreateType().

-or-

For the current dynamic type, the IsGenericType property is true, but the IsGenericTypeDefinition property is false.

Examples

The following code example defines a generic method named DemoMethod whose parameter type and return type are specified by its generic type parameters. The method is defined without a signature, using the standard calling convention. The MethodBuilder.DefineGenericParameters method is used to make DemoMethod a generic method, and the newly defined type parameters are then used for the signature and return type.

This code example is part of a larger example provided for the DefineGenericParameters method.

C#

// 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
);

C#

// 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);

C#

// 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]);

Remarks

Use this method overload when you do not know the method signature at the time you define the method. For example, the parameter types and return type of a generic method might be specified by the method's generic type parameters, which must be defined after the method has been added to the type. The parameters and return type of the method can be set later using the MethodBuilder.SetSignature method.

This method overload defines a method with CallingConventions.Standard. If you need to define a method without a signature, with a different calling convention, use the DefineMethod(String, MethodAttributes, CallingConventions) method overload.

See also

• DefineGenericParameters(String[])

DefineMethod(String, MethodAttributes, Type, Type[])

Source:

TypeBuilder.cs

Adds a new method to the type, with the specified name, method attributes, and method signature.

C#

public System.Reflection.Emit.MethodBuilder DefineMethod(string name, System.Reflection.MethodAttributes attributes, Type? returnType, Type[]? parameterTypes);

Parameters

name

String

The name of the method. name cannot contain embedded nulls.

attributes

MethodAttributes

The attributes of the method.

returnType

Type

The return type of the method.

parameterTypes

Type[]

The types of the parameters of the method.

Returns

MethodBuilder

The defined method.

Exceptions

ArgumentException

The length of name is zero.

-or-

The type of the parent of this method is an interface, and this method is not virtual (Overridable in Visual Basic).

ArgumentNullException

name is null.

InvalidOperationException

The type was previously created using CreateType().

-or-

For the current dynamic type, the IsGenericType property is true, but the IsGenericTypeDefinition property is false.

Examples

The following code sample demonstrates the use of DefineMethod to set a constructor's particular signature and attributes on a dynamic type and to return a corresponding MethodBuilder for MSIL population.

C#

using System;
using System.Threading;
using System.Reflection;
using System.Reflection.Emit;
using System.Security.Permissions;

public interface IMyInterface
{
   String HelloMethod(String parameter);
}

public class Example
{
   public static void Main()
   {
      Type myNestedClassType = CreateCallee(Thread.GetDomain());
      // Cretae an instance of 'MyNestedClass'.
      IMyInterface myInterface =
         (IMyInterface)Activator.CreateInstance(myNestedClassType);
      Console.WriteLine(myInterface.HelloMethod("Bill"));
   }

   // Create the callee transient dynamic assembly.
   private static Type CreateCallee(AppDomain myAppDomain)
   {
      AssemblyName myAssemblyName = new AssemblyName();
      myAssemblyName.Name = "Example";
      // Create the callee dynamic assembly.
      AssemblyBuilder myAssembly =
         myAppDomain.DefineDynamicAssembly(myAssemblyName, AssemblyBuilderAccess.Run);
      // Create a dynamic module in the callee assembly.
      ModuleBuilder myModule = myAssembly.DefineDynamicModule("EmittedModule");
      // Define a public class named "MyHelloWorld".
      TypeBuilder myHelloWorldType =
         myModule.DefineType("MyHelloWorld", TypeAttributes.Public);
      // Define a public nested class named 'MyNestedClass'.
      TypeBuilder myNestedClassType =
         myHelloWorldType.DefineNestedType("MyNestedClass",
            TypeAttributes.NestedPublic, typeof(Example),
            new Type[]{typeof(IMyInterface)});
      // Implement 'IMyInterface' interface.
      myNestedClassType.AddInterfaceImplementation(typeof(IMyInterface));
      // Define 'HelloMethod' of 'IMyInterface'.
      MethodBuilder myHelloMethod =
         myNestedClassType.DefineMethod("HelloMethod",
            MethodAttributes.Public | MethodAttributes.Virtual,
            typeof(String), new Type[]{typeof(String)});
      // Generate IL for 'GetGreeting' method.
      ILGenerator myMethodIL = myHelloMethod.GetILGenerator();
      myMethodIL.Emit(OpCodes.Ldstr, "Hi! ");
      myMethodIL.Emit(OpCodes.Ldarg_1);
      MethodInfo infoMethod =
         typeof(String).GetMethod("Concat",new Type[]{typeof(string),typeof(string)});
      myMethodIL.Emit(OpCodes.Call, infoMethod);
      myMethodIL.Emit(OpCodes.Ret);

      MethodInfo myHelloMethodInfo =
         typeof(IMyInterface).GetMethod("HelloMethod");
      // Implement 'HelloMethod' of 'IMyInterface'.
      myNestedClassType.DefineMethodOverride(myHelloMethod, myHelloMethodInfo);
      // Create 'MyHelloWorld' type.
      Type myType = myHelloWorldType.CreateType();
      // Create 'MyNestedClass' type.
      return myNestedClassType.CreateType();
   }
}