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MethodBuilder.GetILGenerator Method

Returns an ILGenerator for this method.

Overload List

Returns an ILGenerator for this method with a default Microsoft intermediate language (MSIL) stream size of 64 bytes.

[Visual Basic] Overloads Public Function GetILGenerator() As ILGenerator
[C#] public ILGenerator GetILGenerator();
[C++] public: ILGenerator* GetILGenerator();
[JScript] public function GetILGenerator() : ILGenerator;

Returns an ILGenerator for this method with the specified Microsoft intermediate language (MSIL) stream size.

[Visual Basic] Overloads Public Function GetILGenerator(Integer) As ILGenerator
[C#] public ILGenerator GetILGenerator(int);
[C++] public: ILGenerator* GetILGenerator(int);
[JScript] public function GetILGenerator(int) : ILGenerator;

Example

[Visual Basic, C#, C++] The code sample below demonstrates the contextual usage of the GetILGenerator method, creating and emitting a dynamic assembly that will calculate the dot product of two points in 3D space.

[Visual Basic, C#, C++] Note   This example shows how to use one of the overloaded versions of GetILGenerator. For other examples that might be available, see the individual overload topics.
[Visual Basic] 
Imports System
Imports System.Threading
Imports System.Reflection
Imports System.Reflection.Emit

 _


Class TestILGenerator
   
   
   Public Shared Function DynamicDotProductGen() As Type
      
      Dim ivType As Type = Nothing
      Dim ctorParams() As Type = {GetType(Integer), GetType(Integer), GetType(Integer)}
      
      Dim myDomain As AppDomain = Thread.GetDomain()
      Dim myAsmName As New AssemblyName()
      myAsmName.Name = "IntVectorAsm"
      
      Dim myAsmBuilder As AssemblyBuilder = myDomain.DefineDynamicAssembly( _
                        myAsmName, _
                        AssemblyBuilderAccess.RunAndSave)
      
      Dim IntVectorModule As ModuleBuilder = myAsmBuilder.DefineDynamicModule( _
                         "IntVectorModule", _
                         "Vector.dll")
      
      Dim ivTypeBld As TypeBuilder = IntVectorModule.DefineType("IntVector", TypeAttributes.Public)
      
      Dim xField As FieldBuilder = ivTypeBld.DefineField("x", _
                                 GetType(Integer), _
                                 FieldAttributes.Private)
      Dim yField As FieldBuilder = ivTypeBld.DefineField("y", _ 
                                 GetType(Integer), _
                                 FieldAttributes.Private)
      Dim zField As FieldBuilder = ivTypeBld.DefineField("z", _
                                 GetType(Integer), _
                                 FieldAttributes.Private)
      
      
      Dim objType As Type = Type.GetType("System.Object")
      Dim objCtor As ConstructorInfo = objType.GetConstructor(New Type() {})
      
      Dim ivCtor As ConstructorBuilder = ivTypeBld.DefineConstructor( _
                     MethodAttributes.Public, _
                     CallingConventions.Standard, _
                     ctorParams)
      Dim ctorIL As ILGenerator = ivCtor.GetILGenerator()
      ctorIL.Emit(OpCodes.Ldarg_0)
      ctorIL.Emit(OpCodes.Call, objCtor)
      ctorIL.Emit(OpCodes.Ldarg_0)
      ctorIL.Emit(OpCodes.Ldarg_1)
      ctorIL.Emit(OpCodes.Stfld, xField)
      ctorIL.Emit(OpCodes.Ldarg_0)
      ctorIL.Emit(OpCodes.Ldarg_2)
      ctorIL.Emit(OpCodes.Stfld, yField)
      ctorIL.Emit(OpCodes.Ldarg_0)
      ctorIL.Emit(OpCodes.Ldarg_3)
      ctorIL.Emit(OpCodes.Stfld, zField)
      ctorIL.Emit(OpCodes.Ret)
     

      ' Now, you'll construct the method find the dot product of two vectors. First,
      ' let's define the parameters that will be accepted by the method. In this case,
      ' it's an IntVector itself!

      Dim dpParams() As Type = {ivTypeBld}
      
      ' Here, you create a MethodBuilder containing the
      ' name, the attributes (public, static, private, and so on),
      ' the return type (int, in this case), and a array of Type
      ' indicating the type of each parameter. Since the sole parameter
      ' is a IntVector, the very class you're creating, you will
      ' pass in the TypeBuilder (which is derived from Type) instead of 
      ' a Type object for IntVector, avoiding an exception. 
      ' -- This method would be declared in VB.NET as:
      '    Public Function DotProduct(IntVector aVector) As Integer

      Dim dotProductMthd As MethodBuilder = ivTypeBld.DefineMethod("DotProduct", _
                        MethodAttributes.Public, GetType(Integer), _
                                            dpParams)
      
      ' A ILGenerator can now be spawned, attached to the MethodBuilder.
      Dim mthdIL As ILGenerator = dotProductMthd.GetILGenerator()
      
      ' Here's the body of our function, in MSIL form. We're going to find the
      ' "dot product" of the current vector instance with the passed vector 
      ' instance. For reference purposes, the equation is:
      ' (x1 * x2) + (y1 * y2) + (z1 * z2) = the dot product
      ' First, you'll load the reference to the current instance "this"
      ' stored in argument 0 (ldarg.0) onto the stack. Ldfld, the subsequent
      ' instruction, will pop the reference off the stack and look up the
      ' field "x", specified by the FieldInfo token "xField".
      mthdIL.Emit(OpCodes.Ldarg_0)
      mthdIL.Emit(OpCodes.Ldfld, xField)
      
      ' That completed, the value stored at field "x" is now atop the stack.
      ' Now, you'll do the same for the object reference we passed as a
      ' parameter, stored in argument 1 (ldarg.1). After Ldfld executed,
      ' you'll have the value stored in field "x" for the passed instance
      ' atop the stack.
      mthdIL.Emit(OpCodes.Ldarg_1)
      mthdIL.Emit(OpCodes.Ldfld, xField)
      
      ' There will now be two values atop the stack - the "x" value for the
      ' current vector instance, and the "x" value for the passed instance.
      ' You'll now multiply them, and push the result onto the evaluation stack.
      mthdIL.Emit(OpCodes.Mul_Ovf_Un)
      
      ' Now, repeat this for the "y" fields of both vectors.
      mthdIL.Emit(OpCodes.Ldarg_0)
      mthdIL.Emit(OpCodes.Ldfld, yField)
      mthdIL.Emit(OpCodes.Ldarg_1)
      mthdIL.Emit(OpCodes.Ldfld, yField)
      mthdIL.Emit(OpCodes.Mul_Ovf_Un)
      
      ' At this time, the results of both multiplications should be atop
      ' the stack. You'll now add them and push the result onto the stack.
      mthdIL.Emit(OpCodes.Add_Ovf_Un)
      
      ' Multiply both "z" field and push the result onto the stack.
      mthdIL.Emit(OpCodes.Ldarg_0)
      mthdIL.Emit(OpCodes.Ldfld, zField)
      mthdIL.Emit(OpCodes.Ldarg_1)
      mthdIL.Emit(OpCodes.Ldfld, zField)
      mthdIL.Emit(OpCodes.Mul_Ovf_Un)
      
      ' Finally, add the result of multiplying the "z" fields with the
      ' result of the earlier addition, and push the result - the dot product -
      ' onto the stack.
      mthdIL.Emit(OpCodes.Add_Ovf_Un)
      
      ' The "ret" opcode will pop the last value from the stack and return it
      ' to the calling method. You're all done!
      mthdIL.Emit(OpCodes.Ret)
      
      
      ivType = ivTypeBld.CreateType()
      
      Return ivType
   End Function 'DynamicDotProductGen
    
   
   Public Shared Sub Main()
      
      Dim IVType As Type = Nothing
      Dim aVector1 As Object = Nothing
      Dim aVector2 As Object = Nothing
      Dim aVtypes() As Type = {GetType(Integer), GetType(Integer), GetType(Integer)}
      Dim aVargs1() As Object = {10, 10, 10}
      Dim aVargs2() As Object = {20, 20, 20}
      
      ' Call the  method to build our dynamic class.
      IVType = DynamicDotProductGen()
      
      
      Dim myDTctor As ConstructorInfo = IVType.GetConstructor(aVtypes)
      aVector1 = myDTctor.Invoke(aVargs1)
      aVector2 = myDTctor.Invoke(aVargs2)
      
      Console.WriteLine("---")
      Dim passMe(0) As Object
      passMe(0) = CType(aVector2, Object)
      
      Console.WriteLine("(10, 10, 10) . (20, 20, 20) = {0}", _
                        IVType.InvokeMember("DotProduct", BindingFlags.InvokeMethod, _
                        Nothing, aVector1, passMe))
   End Sub 'Main
End Class 'TestILGenerator



' +++ OUTPUT +++
' ---
' (10, 10, 10) . (20, 20, 20) = 600 



[C#] 

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


class TestILGenerator {
 
      public static Type DynamicDotProductGen() {
      
       Type ivType = null;
       Type[] ctorParams = new Type[] { typeof(int),
                                   typeof(int),
                        typeof(int)};
     
       AppDomain myDomain = Thread.GetDomain();
       AssemblyName myAsmName = new AssemblyName();
       myAsmName.Name = "IntVectorAsm";
    
       AssemblyBuilder myAsmBuilder = myDomain.DefineDynamicAssembly(
                      myAsmName, 
                      AssemblyBuilderAccess.RunAndSave);

          ModuleBuilder IntVectorModule = myAsmBuilder.DefineDynamicModule("IntVectorModule",
                                        "Vector.dll");

       TypeBuilder ivTypeBld = IntVectorModule.DefineType("IntVector",
                                      TypeAttributes.Public);

       FieldBuilder xField = ivTypeBld.DefineField("x", typeof(int),
                                                       FieldAttributes.Private);
       FieldBuilder yField = ivTypeBld.DefineField("y", typeof(int), 
                                                       FieldAttributes.Private);
       FieldBuilder zField = ivTypeBld.DefineField("z", typeof(int),
                                                       FieldAttributes.Private);


           Type objType = Type.GetType("System.Object"); 
           ConstructorInfo objCtor = objType.GetConstructor(new Type[0]);

       ConstructorBuilder ivCtor = ivTypeBld.DefineConstructor(
                      MethodAttributes.Public,
                      CallingConventions.Standard,
                      ctorParams);
       ILGenerator ctorIL = ivCtor.GetILGenerator();
           ctorIL.Emit(OpCodes.Ldarg_0);
           ctorIL.Emit(OpCodes.Call, objCtor);
           ctorIL.Emit(OpCodes.Ldarg_0);
           ctorIL.Emit(OpCodes.Ldarg_1);
           ctorIL.Emit(OpCodes.Stfld, xField); 
           ctorIL.Emit(OpCodes.Ldarg_0);
           ctorIL.Emit(OpCodes.Ldarg_2);
           ctorIL.Emit(OpCodes.Stfld, yField); 
           ctorIL.Emit(OpCodes.Ldarg_0);
           ctorIL.Emit(OpCodes.Ldarg_3);
           ctorIL.Emit(OpCodes.Stfld, zField); 
       ctorIL.Emit(OpCodes.Ret); 


       // This method will find the dot product of the stored vector
       // with another.

       Type[] dpParams = new Type[] { ivTypeBld };

           // Here, you create a MethodBuilder containing the
       // name, the attributes (public, static, private, and so on),
       // the return type (int, in this case), and a array of Type
       // indicating the type of each parameter. Since the sole parameter
       // is a IntVector, the very class you're creating, you will
       // pass in the TypeBuilder (which is derived from Type) instead of 
       // a Type object for IntVector, avoiding an exception. 

       // -- This method would be declared in C# as:
       //    public int DotProduct(IntVector aVector)

           MethodBuilder dotProductMthd = ivTypeBld.DefineMethod(
                                  "DotProduct", 
                          MethodAttributes.Public,
                                          typeof(int), 
                                          dpParams);

       // A ILGenerator can now be spawned, attached to the MethodBuilder.

       ILGenerator mthdIL = dotProductMthd.GetILGenerator();
       
        // Here's the body of our function, in MSIL form. We're going to find the
       // "dot product" of the current vector instance with the passed vector 
       // instance. For reference purposes, the equation is:
       // (x1 * x2) + (y1 * y2) + (z1 * z2) = the dot product

       // First, you'll load the reference to the current instance "this"
       // stored in argument 0 (ldarg.0) onto the stack. Ldfld, the subsequent
       // instruction, will pop the reference off the stack and look up the
       // field "x", specified by the FieldInfo token "xField".

       mthdIL.Emit(OpCodes.Ldarg_0);
       mthdIL.Emit(OpCodes.Ldfld, xField);

       // That completed, the value stored at field "x" is now atop the stack.
       // Now, you'll do the same for the object reference we passed as a
       // parameter, stored in argument 1 (ldarg.1). After Ldfld executed,
       // you'll have the value stored in field "x" for the passed instance
       // atop the stack.

       mthdIL.Emit(OpCodes.Ldarg_1);
       mthdIL.Emit(OpCodes.Ldfld, xField);

           // There will now be two values atop the stack - the "x" value for the
       // current vector instance, and the "x" value for the passed instance.
       // You'll now multiply them, and push the result onto the evaluation stack.

       mthdIL.Emit(OpCodes.Mul_Ovf_Un);

       // Now, repeat this for the "y" fields of both vectors.

       mthdIL.Emit(OpCodes.Ldarg_0);
       mthdIL.Emit(OpCodes.Ldfld, yField);
       mthdIL.Emit(OpCodes.Ldarg_1);
       mthdIL.Emit(OpCodes.Ldfld, yField);
       mthdIL.Emit(OpCodes.Mul_Ovf_Un);

       // At this time, the results of both multiplications should be atop
       // the stack. You'll now add them and push the result onto the stack.

       mthdIL.Emit(OpCodes.Add_Ovf_Un);

       // Multiply both "z" field and push the result onto the stack.
       mthdIL.Emit(OpCodes.Ldarg_0);
       mthdIL.Emit(OpCodes.Ldfld, zField);
       mthdIL.Emit(OpCodes.Ldarg_1);
       mthdIL.Emit(OpCodes.Ldfld, zField);
       mthdIL.Emit(OpCodes.Mul_Ovf_Un);

       // Finally, add the result of multiplying the "z" fields with the
       // result of the earlier addition, and push the result - the dot product -
       // onto the stack.
       mthdIL.Emit(OpCodes.Add_Ovf_Un);

       // The "ret" opcode will pop the last value from the stack and return it
       // to the calling method. You're all done!

       mthdIL.Emit(OpCodes.Ret);


        ivType = ivTypeBld.CreateType();

       return ivType;

     }

    public static void Main() {
    
       Type IVType = null;
           object aVector1 = null;
           object aVector2 = null;
       Type[] aVtypes = new Type[] {typeof(int), typeof(int), typeof(int)};
           object[] aVargs1 = new object[] {10, 10, 10};
           object[] aVargs2 = new object[] {20, 20, 20};
    
       // Call the  method to build our dynamic class.

       IVType = DynamicDotProductGen();

           Console.WriteLine("---");

       ConstructorInfo myDTctor = IVType.GetConstructor(aVtypes);
       aVector1 = myDTctor.Invoke(aVargs1);
       aVector2 = myDTctor.Invoke(aVargs2);

       object[] passMe = new object[1];
           passMe[0] = (object)aVector2; 

       Console.WriteLine("(10, 10, 10) . (20, 20, 20) = {0}",
                 IVType.InvokeMember("DotProduct",
                          BindingFlags.InvokeMethod,
                          null,
                          aVector1,
                          passMe));

        

       // +++ OUTPUT +++
       // ---
       // (10, 10, 10) . (20, 20, 20) = 600 
        
    }
    
}


[C++] 

#using <mscorlib.dll>

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

Type* DynamicDotProductGen() {

   Type* ivType = 0;

   Type* temp0 [] = {__typeof(int), __typeof(int), __typeof(int)};
   Type* ctorParams[] = temp0;

   AppDomain*  myDomain = Thread::GetDomain();
   AssemblyName* myAsmName = new AssemblyName();
   myAsmName->Name = S"IntVectorAsm";

   AssemblyBuilder*  myAsmBuilder = myDomain->DefineDynamicAssembly(myAsmName,
      AssemblyBuilderAccess::RunAndSave);

   ModuleBuilder*  IntVectorModule = myAsmBuilder->DefineDynamicModule(S"IntVectorModule",
      S"Vector.dll");

   TypeBuilder*  ivTypeBld = IntVectorModule->DefineType(S"IntVector",
      TypeAttributes::Public);

   FieldBuilder*  xField = ivTypeBld->DefineField(S"x", __typeof(int),
      FieldAttributes::Private);
   FieldBuilder*  yField = ivTypeBld->DefineField(S"y", __typeof(int),
      FieldAttributes::Private);
   FieldBuilder*  zField = ivTypeBld->DefineField(S"z", __typeof(int),
      FieldAttributes::Private);


   Type*  objType = Type::GetType(S"System.Object");
   ConstructorInfo*  objCtor = objType->GetConstructor(new Type*[0]);

   ConstructorBuilder*  ivCtor = ivTypeBld->DefineConstructor(MethodAttributes::Public,
      CallingConventions::Standard,
      ctorParams);
   ILGenerator*  ctorIL = ivCtor->GetILGenerator();
   ctorIL->Emit(OpCodes::Ldarg_0);
   ctorIL->Emit(OpCodes::Call, objCtor);
   ctorIL->Emit(OpCodes::Ldarg_0);
   ctorIL->Emit(OpCodes::Ldarg_1);
   ctorIL->Emit(OpCodes::Stfld, xField);
   ctorIL->Emit(OpCodes::Ldarg_0);
   ctorIL->Emit(OpCodes::Ldarg_2);
   ctorIL->Emit(OpCodes::Stfld, yField);
   ctorIL->Emit(OpCodes::Ldarg_0);
   ctorIL->Emit(OpCodes::Ldarg_3);
   ctorIL->Emit(OpCodes::Stfld, zField);
   ctorIL->Emit(OpCodes::Ret);

   // This method will find the dot product of the stored vector
   // with another.

   Type* temp1 [] = {ivTypeBld};
   Type* dpParams[] = temp1;

   // Here, you create a MethodBuilder containing the
   // name, the attributes (public, static, private, and so on),
   // the return type (int, in this case), and a array of Type
   // indicating the type of each parameter. Since the sole parameter
   // is a IntVector, the very class you're creating, you will
   // pass in the TypeBuilder (which is derived from Type) instead of
   // a Type object for IntVector, avoiding an exception.

   // -- This method would be declared in C# as:
   //    public int DotProduct(IntVector aVector)

   MethodBuilder*  dotProductMthd = ivTypeBld->DefineMethod(S"DotProduct",
      MethodAttributes::Public,
      __typeof(int),
      dpParams);

   // A ILGenerator can now be spawned, attached to the MethodBuilder.

   ILGenerator*  mthdIL = dotProductMthd->GetILGenerator();

   // Here's the body of our function, in MSIL form. We're going to find the
   // "dot product" of the current vector instance with the passed vector
   // instance. For reference purposes, the equation is:
   // (x1 * x2) + (y1 * y2) + (z1 * z2) = the dot product

   // First, you'll load the reference to the current instance "this"
   // stored in argument 0 (ldarg.0) onto the stack. Ldfld, the subsequent
   // instruction, will pop the reference off the stack and look up the
   // field "x", specified by the FieldInfo token "xField".

   mthdIL->Emit(OpCodes::Ldarg_0);
   mthdIL->Emit(OpCodes::Ldfld, xField);

   // That completed, the value stored at field "x" is now atop the stack.
   // Now, you'll do the same for the Object reference we passed as a
   // parameter, stored in argument 1 (ldarg.1). After Ldfld executed,
   // you'll have the value stored in field "x" for the passed instance
   // atop the stack.

   mthdIL->Emit(OpCodes::Ldarg_1);
   mthdIL->Emit(OpCodes::Ldfld, xField);

   // There will now be two values atop the stack - the "x" value for the
   // current vector instance, and the "x" value for the passed instance.
   // You'll now multiply them, and push the result onto the evaluation stack.

   mthdIL->Emit(OpCodes::Mul_Ovf_Un);

   // Now, repeat this for the "y" fields of both vectors.

   mthdIL->Emit(OpCodes::Ldarg_0);
   mthdIL->Emit(OpCodes::Ldfld, yField);
   mthdIL->Emit(OpCodes::Ldarg_1);
   mthdIL->Emit(OpCodes::Ldfld, yField);
   mthdIL->Emit(OpCodes::Mul_Ovf_Un);

   // At this time, the results of both multiplications should be atop
   // the stack. You'll now add them and push the result onto the stack.

   mthdIL->Emit(OpCodes::Add_Ovf_Un);

   // Multiply both "z" field and push the result onto the stack.
   mthdIL->Emit(OpCodes::Ldarg_0);
   mthdIL->Emit(OpCodes::Ldfld, zField);
   mthdIL->Emit(OpCodes::Ldarg_1);
   mthdIL->Emit(OpCodes::Ldfld, zField);
   mthdIL->Emit(OpCodes::Mul_Ovf_Un);

   // Finally, add the result of multiplying the "z" fields with the
   // result of the earlier addition, and push the result - the dot product -
   // onto the stack.
   mthdIL->Emit(OpCodes::Add_Ovf_Un);

   // The "ret" opcode will pop the last value from the stack and return it
   // to the calling method. You're all done!

   mthdIL->Emit(OpCodes::Ret);

   ivType = ivTypeBld->CreateType();

   return ivType;
}

int main() {

   Type* IVType = 0;
   Object* aVector1 = 0;
   Object* aVector2 = 0;

   Type* temp2 [] = {__typeof(int), __typeof(int), __typeof(int)};
   Type* aVtypes[] = temp2;

   Object* temp3 [] = {__box(10), __box(10), __box(10)};
   Object* aVargs1[] = temp3;

   Object* temp4 [] = {__box(20), __box(20), __box(20)};
   Object* aVargs2[] = temp4;

   // Call the  method to build our dynamic class.

   IVType = DynamicDotProductGen();

   Console::WriteLine(S"---");

   ConstructorInfo*  myDTctor = IVType->GetConstructor(aVtypes);
   aVector1 = myDTctor->Invoke(aVargs1);
   aVector2 = myDTctor->Invoke(aVargs2);

   Object* passMe[] = new Object*[1];
   passMe->Item[0] = dynamic_cast<Object*>(aVector2);

   Console::WriteLine(S"(10, 10, 10) . (20, 20, 20) = {0}",
      IVType->InvokeMember(S"DotProduct",
      BindingFlags::InvokeMethod,
      0,
      aVector1,
      passMe));
}

   // +++ OUTPUT +++
   // ---
   // (10, 10, 10) . (20, 20, 20) = 600

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.

See Also

MethodBuilder Class | MethodBuilder Members | System.Reflection.Emit Namespace

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