MethodBuilder.CreateMethodBody(Byte[], Int32) Method

Reference

Definition

Namespace:: System.Reflection.Emit

Assembly:: mscorlib.dll

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Creates the body of the method using a supplied byte array of Microsoft intermediate language (MSIL) instructions.

public:
 void CreateMethodBody(cli::array <System::Byte> ^ il, int count);

public void CreateMethodBody (byte[] il, int count);

member this.CreateMethodBody : byte[] * int -> unit

Public Sub CreateMethodBody (il As Byte(), count As Integer)

Parameters

il: Byte[]

An array containing valid MSIL instructions. If this parameter is null, the method's body is cleared.

count: Int32

The number of valid bytes in the MSIL array. This value is ignored if MSIL is null.

Exceptions

ArgumentOutOfRangeException

The count is not within the range of indexes of the supplied MSIL instruction array and il is not null.

InvalidOperationException

The containing type was previously created using CreateType().

-or-

This method was called previously on this MethodBuilder with an il argument that was not null.

-or-

For the current method, the IsGenericMethod property is true, but the IsGenericMethodDefinition property is false.

Examples

In the example provided below, a simple method that adds two integers is generated via opcode using CreateMethodBody.

using namespace System;
using namespace System::Threading;
using namespace System::Reflection;
using namespace System::Reflection::Emit;
class MethodBodyDemo
{
public:

   // This class will demonstrate how to create a method body using
   // the MethodBuilder::CreateMethodBody(Byte[], int) method.
   static Type^ BuildDynType()
   {
      Type^ addType = nullptr;
      AppDomain^ currentDom = Thread::GetDomain();
      AssemblyName^ myAsmName = gcnew AssemblyName;
      myAsmName->Name = "MyDynamicAssembly";
      AssemblyBuilder^ myAsmBldr = currentDom->DefineDynamicAssembly( myAsmName, AssemblyBuilderAccess::RunAndSave );
      
      // The dynamic assembly space has been created.  Next, create a module
      // within it.  The type Point will be reflected into this module.
      ModuleBuilder^ myModuleBldr = myAsmBldr->DefineDynamicModule( "MyModule" );
      TypeBuilder^ myTypeBldr = myModuleBldr->DefineType( "Adder" );
      array<Type^>^temp0 = {int::typeid,int::typeid};
      MethodBuilder^ myMthdBldr = myTypeBldr->DefineMethod( "DoAdd", static_cast<MethodAttributes>(MethodAttributes::Public | MethodAttributes::Static), int::typeid, temp0 );
      
      // Build the array of Bytes holding the MSIL instructions.
      
      /* 02h is the opcode for ldarg.0 */
      /* 03h is the opcode for ldarg.1 */
      /* 58h is the opcode for add     */
      /* 2Ah is the opcode for ret     */
      array<Byte>^temp1 = {0x02,0x03,0x58,0x2A};
      array<Byte>^ILcodes = temp1;
      myMthdBldr->CreateMethodBody( ILcodes, ILcodes->Length );
      addType = myTypeBldr->CreateType();
      return addType;
   }

};

int main()
{
   Type^ myType = MethodBodyDemo::BuildDynType();
   Console::WriteLine( "---" );
   Console::Write( "Enter the first integer to add: " );
   int aVal = Convert::ToInt32( Console::ReadLine() );
   Console::Write( "Enter the second integer to add: " );
   int bVal = Convert::ToInt32( Console::ReadLine() );
   Object^ adderInst = Activator::CreateInstance( myType, gcnew array<Object^>(0) );
   array<Object^>^temp1 = {aVal,bVal};
   Console::WriteLine( "The value of adding {0} to {1} is: {2}.", aVal, bVal, myType->InvokeMember( "DoAdd", BindingFlags::InvokeMethod, nullptr, adderInst, temp1 ) );
}


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

class MethodBodyDemo {
// This class will demonstrate how to create a method body using
// the MethodBuilder.CreateMethodBody(byte[], int) method.

   public static Type BuildDynType() {

    Type addType = null;

        AppDomain currentDom = Thread.GetDomain();

        AssemblyName myAsmName = new AssemblyName();
    myAsmName.Name = "MyDynamicAssembly";

        AssemblyBuilder myAsmBldr = currentDom.DefineDynamicAssembly(
                           myAsmName,
                           AssemblyBuilderAccess.RunAndSave);

        // The dynamic assembly space has been created.  Next, create a module
        // within it.  The type Point will be reflected into this module.

    ModuleBuilder myModuleBldr = myAsmBldr.DefineDynamicModule("MyModule");

    TypeBuilder myTypeBldr =  myModuleBldr.DefineType("Adder");

        MethodBuilder myMthdBldr = myTypeBldr.DefineMethod("DoAdd",
                                MethodAttributes.Public |
                                MethodAttributes.Static,
                                typeof(int),
                                new Type[]
                                {typeof(int), typeof(int)});
        // Build the array of Bytes holding the MSIL instructions.

        byte[] ILcodes = new byte[] {
          0x02,   /* 02h is the opcode for ldarg.0 */
      0x03,   /* 03h is the opcode for ldarg.1 */
      0x58,   /* 58h is the opcode for add     */
      0x2A    /* 2Ah is the opcode for ret     */
    };
    
    myMthdBldr.CreateMethodBody(ILcodes, ILcodes.Length);

        addType = myTypeBldr.CreateType();

    return addType;
   }

   public static void Main() {

    Type myType = BuildDynType();
        Console.WriteLine("---");
    Console.Write("Enter the first integer to add: ");
        int aVal = Convert.ToInt32(Console.ReadLine());

        Console.Write("Enter the second integer to add: ");
        int bVal = Convert.ToInt32(Console.ReadLine());

        object adderInst = Activator.CreateInstance(myType, new object[0]);

    Console.WriteLine("The value of adding {0} to {1} is: {2}.",
               aVal, bVal,	
                   myType.InvokeMember("DoAdd",
                           BindingFlags.InvokeMethod,
                           null,
                           adderInst,
                           new object[] {aVal, bVal}));
   }
}

Imports System.Threading
Imports System.Reflection
Imports System.Reflection.Emit

 _

Class MethodBodyDemo
   
   ' This class will demonstrate how to create a method body using 
   ' the MethodBuilder.CreateMethodBody(byte[], int) method.

   Public Shared Function BuildDynType() As Type
      
      Dim addType As Type = Nothing
      
      Dim currentDom As AppDomain = Thread.GetDomain()
      
      Dim myAsmName As New AssemblyName()
      myAsmName.Name = "MyDynamicAssembly"
      
      Dim myAsmBldr As AssemblyBuilder = currentDom.DefineDynamicAssembly(myAsmName, _
                         AssemblyBuilderAccess.RunAndSave)
      
      ' The dynamic assembly space has been created.  Next, create a module
      ' within it.  The type Point will be reflected into this module.
      Dim myModuleBldr As ModuleBuilder = myAsmBldr.DefineDynamicModule("MyModule")
      
      Dim myTypeBldr As TypeBuilder = myModuleBldr.DefineType("Adder")
      
      Dim myMthdBldr As MethodBuilder = myTypeBldr.DefineMethod("DoAdd", _
                    MethodAttributes.Public Or MethodAttributes.Static, _
                        GetType(Integer), _
                    New Type() {GetType(Integer), GetType(Integer)})

      ' Build the array of Bytes holding the MSIL instructions.

      Dim ILcodes() As Byte = {&H2, &H3, &H58, &H2A}

      ' 02h is the opcode for ldarg.0 
      ' 03h is the opcode for ldarg.1 
      ' 58h is the opcode for add     
      ' 2Ah is the opcode for ret     
      
      myMthdBldr.CreateMethodBody(ILcodes, ILcodes.Length)
      
      addType = myTypeBldr.CreateType()
      
      Return addType

   End Function 'BuildDynType
   
   
   Public Shared Sub Main()
      
      Dim myType As Type = BuildDynType()
      Console.WriteLine("---")
      Console.Write("Enter the first integer to add: ")
      Dim aVal As Integer = Convert.ToInt32(Console.ReadLine())
      
      Console.Write("Enter the second integer to add: ")
      Dim bVal As Integer = Convert.ToInt32(Console.ReadLine())
      
      Dim adderInst As Object = Activator.CreateInstance(myType, New Object() {})
      
      Console.WriteLine("The value of adding {0} to {1} is: {2}.", _
             aVal, bVal, _
             myType.InvokeMember("DoAdd", _
                          BindingFlags.InvokeMethod, _
                          Nothing, _
                          adderInst, _
                          New Object() {aVal, bVal}))

   End Sub

End Class

Remarks

This method creates the method's body from il, an array containing MSIL instructions as opcodes. The number of bytes of valid MSIL is given by count.

Note

This is currently not fully supported. The user cannot supply the location of token fix ups and exception handlers.

Applies to

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