ModuleBuilder.DefinePInvokeMethod Method (System.Reflection.Emit) (original) (raw)

Source:

Defines a PInvoke method with the specified name, the name of the DLL in which the method is defined, the attributes of the method, the calling convention of the method, the return type of the method, the types of the parameters of the method, and the PInvoke flags.

public:
 System::Reflection::Emit::MethodBuilder ^ DefinePInvokeMethod(System::String ^ name, System::String ^ dllName, System::String ^ entryName, System::Reflection::MethodAttributes attributes, System::Reflection::CallingConventions callingConvention, Type ^ returnType, cli::array <Type ^> ^ parameterTypes, System::Runtime::InteropServices::CallingConvention nativeCallConv, System::Runtime::InteropServices::CharSet nativeCharSet);

public System.Reflection.Emit.MethodBuilder DefinePInvokeMethod(string name, string dllName, string entryName, System.Reflection.MethodAttributes attributes, System.Reflection.CallingConventions callingConvention, Type? returnType, Type[]? parameterTypes, System.Runtime.InteropServices.CallingConvention nativeCallConv, System.Runtime.InteropServices.CharSet nativeCharSet);

public System.Reflection.Emit.MethodBuilder DefinePInvokeMethod(string name, string dllName, string entryName, System.Reflection.MethodAttributes attributes, System.Reflection.CallingConventions callingConvention, Type returnType, Type[] parameterTypes, System.Runtime.InteropServices.CallingConvention nativeCallConv, System.Runtime.InteropServices.CharSet nativeCharSet);

member this.DefinePInvokeMethod : string * string * string * System.Reflection.MethodAttributes * System.Reflection.CallingConventions * Type * Type[] * System.Runtime.InteropServices.CallingConvention * System.Runtime.InteropServices.CharSet -> System.Reflection.Emit.MethodBuilder

Public Function DefinePInvokeMethod (name As String, dllName As String, entryName As String, attributes As MethodAttributes, callingConvention As CallingConventions, returnType As Type, parameterTypes As Type(), nativeCallConv As CallingConvention, nativeCharSet As CharSet) As MethodBuilder

Parameters

name

String

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

dllName

String

The name of the DLL in which the PInvoke method is defined.

entryName

String

The name of the entry point in the DLL.

returnType

Type

The method's return type.

parameterTypes

Type[]

The types of the method's parameters.

nativeCharSet

CharSet

The method's native character set.

Returns

The defined PInvoke method.

Exceptions

The method is not static or if the containing type is an interface or if the method is abstract of if the method was previously defined.

The containing type has been previously created using CreateType()

Examples

The following example illustrates the use of the DefinePInvokeMethod method to create a MethodBuilder for an external unmanaged method, MessageBoxA, in the Windows API. The example displays a message box with Retry and Cancel buttons, and displays the return value from the message box.

This example uses a different overload of the DefinePInvokeMethod method, but the technique is the same.

using System;
using System.Reflection;
using System.Reflection.Emit;
using System.Runtime.InteropServices;

namespace PInvoke
{
   public class Example
   {
      const int MB_RETRYCANCEL = 5;

      static void Main()
      {
         AssemblyName myAssemblyName = new AssemblyName("TempAssembly");

         // Define a dynamic assembly in the current application domain.
         AssemblyBuilder myAssemblyBuilder =
            AppDomain.CurrentDomain.DefineDynamicAssembly(
                        myAssemblyName, AssemblyBuilderAccess.Run);

         // Define a dynamic module in "TempAssembly" assembly.
         ModuleBuilder myModuleBuilder =
            myAssemblyBuilder.DefineDynamicModule("TempModule");

         Type[] paramTypes = { typeof(int), typeof(string), typeof(string), typeof(int) };

         // Define a PInvoke method.
         MethodBuilder piMethodBuilder = myModuleBuilder.DefinePInvokeMethod(
            "MessageBoxA",
            "user32.dll",
            MethodAttributes.Public | MethodAttributes.Static | MethodAttributes.PinvokeImpl,
            CallingConventions.Standard,
            typeof(int),
            paramTypes,
            CallingConvention.Winapi,
            CharSet.Ansi);

         // Add PreserveSig to the method implementation flags. NOTE: If this line
         // is commented out, the return value will be zero when the method is
         // invoked.
         piMethodBuilder.SetImplementationFlags(
            piMethodBuilder.GetMethodImplementationFlags() | MethodImplAttributes.PreserveSig);

         // Create global methods.
         myModuleBuilder.CreateGlobalFunctions();

         // Arguments for calling the method.
         Object[] arguments = { 0, "Hello World", "Title", MB_RETRYCANCEL };

         MethodInfo pinvokeMethod = myModuleBuilder.GetMethod("MessageBoxA");
         Console.WriteLine("Testing module-level PInvoke method created with DefinePInvokeMethod...");
         Console.WriteLine("Message box returned: {0}",
            pinvokeMethod.Invoke(null, arguments));
      }
   }
}

/* This code example produces input similar to the following:

Testing module-level PInvoke method created with DefinePInvokeMethod...
Message box returned: 4
 */

Imports System.Reflection
Imports System.Reflection.Emit
Imports System.Runtime.InteropServices

Namespace PInvoke

   Public Class Example
   
      Const MB_RETRYCANCEL As Integer = 5

      Shared Sub Main()
      
         Dim myAssemblyName As New AssemblyName("TempAssembly")

         ' Define a dynamic assembly in the current application domain.
         Dim myAssemblyBuilder As AssemblyBuilder = _
            AppDomain.CurrentDomain.DefineDynamicAssembly( _
                        myAssemblyName, AssemblyBuilderAccess.Run)

         ' Define a dynamic module in "TempAssembly" assembly.
         Dim myModuleBuilder As ModuleBuilder = _
            myAssemblyBuilder.DefineDynamicModule("TempModule")

         Dim paramTypes() As Type = _
            { GetType(Integer), GetType(string), GetType(string), GetType(Integer) }

         ' Define a PInvoke method.
         Dim piMethodBuilder As MethodBuilder = myModuleBuilder.DefinePInvokeMethod( _
            "MessageBoxA", _
            "user32.dll", _
            MethodAttributes.Public Or MethodAttributes.Static Or MethodAttributes.PinvokeImpl, _
            CallingConventions.Standard, _
            GetType(Integer), _
            paramTypes, _
            CallingConvention.Winapi, _
            CharSet.Ansi)
         
         ' Add PreserveSig to the method implementation flags. NOTE: If this line
         ' is commented out, the return value will be zero when the method is
         ' invoked.
         piMethodBuilder.SetImplementationFlags( _
            piMethodBuilder.GetMethodImplementationFlags() Or MethodImplAttributes.PreserveSig)

         ' Create global methods.
         myModuleBuilder.CreateGlobalFunctions()

         ' Arguments for calling the method.
         Dim arguments() As Object= { 0, "Hello World", "Title", MB_RETRYCANCEL }

         Dim pinvokeMethod As MethodInfo = _
            myModuleBuilder.GetMethod("MessageBoxA")
         Console.WriteLine("Testing module-level PInvoke method created with DefinePInvokeMethod...")
         Console.WriteLine("Message box returned: {0}", _
            pinvokeMethod.Invoke(Nothing, arguments))

      End Sub
   End Class
End Namespace

' This code example produces input similar to the following:
'
'Testing module-level PInvoke method created with DefinePInvokeMethod...
'Message box returned: 4

Remarks

Some DLL import attributes (see the description of DllImportAttribute) cannot be specified as arguments to this method. Such attributes should be set by emitting a custom attribute for the method. For example, the DLL import attribute PreserveSig is set by emitting a custom attribute.

ModuleBuilder.DefinePInvokeMethod Method (System.Reflection.Emit) (original) (raw)

Parameters

Returns

Exceptions

Examples

Remarks

Applies to