LocalBuilder Class

Imports System.Reflection
Imports System.Reflection.Emit

Class Example

   Public Shared Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)

      ' Create an assembly.
      Dim myAssemblyName As New AssemblyName("SampleAssembly")

      Dim myAssembly As AssemblyBuilder = _
          AppDomain.CurrentDomain.DefineDynamicAssembly(myAssemblyName, _
                           AssemblyBuilderAccess.Run)

      ' Create a module. For a single-file assembly the module
      ' name is usually the same as the assembly name.
      Dim myModule As ModuleBuilder = _
          myAssembly.DefineDynamicModule(myAssemblyName.Name)

      ' Define a public class 'MyExample'.
      Dim myTypeBuilder As TypeBuilder = _
          myModule.DefineType("MyExample", TypeAttributes.Public)

      ' Create the 'Function1' public method, which takes an Integer
      ' and returns a string.
      Dim myMethod As MethodBuilder = myTypeBuilder.DefineMethod("Function1", _
          MethodAttributes.Public Or MethodAttributes.Static, _
          GetType(String), New Type() {GetType(Integer)})

      ' Generate IL for 'Function1'. The function body demonstrates
      ' assigning an argument to a local variable, assigning a 
      ' constant string to a local variable, and putting the contents
      ' of local variables on the stack.
      Dim myMethodIL As ILGenerator = myMethod.GetILGenerator()

      ' Create local variables named myString and myInt.
      Dim myLB1 As LocalBuilder = myMethodIL.DeclareLocal(GetType(String))
      outputBlock.Text &= String.Format("local 'myString' type is: {0}", myLB1.LocalType) & vbCrLf

      Dim myLB2 As LocalBuilder = myMethodIL.DeclareLocal(GetType(Integer))
      outputBlock.Text &= String.Format("local 'myInt' type is: {0}", myLB2.LocalType) & vbCrLf

      ' Store the function argument in myInt.
      myMethodIL.Emit(OpCodes.Ldarg_0)
      myMethodIL.Emit(OpCodes.Stloc_1)

      ' Store a literal value in myString, and return the value.
      myMethodIL.Emit(OpCodes.Ldstr, "string value")
      myMethodIL.Emit(OpCodes.Stloc_0)
      myMethodIL.Emit(OpCodes.Ldloc_0)
      myMethodIL.Emit(OpCodes.Ret)

      ' Create "Example" class.
      Dim myType1 As Type = myTypeBuilder.CreateType()

      ' Invoke 'Function1' method of 'MyExample', passing the value 42.
      Dim myObject2 As Object = myType1.InvokeMember("Function1", _
          BindingFlags.InvokeMethod, Nothing, Nothing, New Object() {42})

      outputBlock.Text &= String.Format("Example.Function1 returned: {0}", myObject2) & vbCrLf

   End Sub
End Class

' This code example produces the following output:
'
'local 'myString' type is: System.String
'local 'myInt' type is: System.Int32
'Example.Function1 returned: string value

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

class Example
{
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      // Create an assembly.
      AssemblyName myAssemblyName = new AssemblyName("SampleAssembly");

      AssemblyBuilder myAssembly =
         AppDomain.CurrentDomain.DefineDynamicAssembly(myAssemblyName,
             AssemblyBuilderAccess.Run);

      // Create a module. For a single-file assembly the module
      // name is usually the same as the assembly name.
      ModuleBuilder myModule =
          myAssembly.DefineDynamicModule(myAssemblyName.Name);

      // Define a public class 'Example'.
      TypeBuilder myTypeBuilder =
          myModule.DefineType("Example", TypeAttributes.Public);

      // Create the 'Function1' public method, which takes an integer
      // and returns a string.
      MethodBuilder myMethod = myTypeBuilder.DefineMethod("Function1",
         MethodAttributes.Public | MethodAttributes.Static,
         typeof(String), new Type[] { typeof(int) });

      // Generate IL for 'Function1'. The function body demonstrates
      // assigning an argument to a local variable, assigning a 
      // constant string to a local variable, and putting the contents
      // of local variables on the stack.
      ILGenerator myMethodIL = myMethod.GetILGenerator();

      // Create local variables named myString and myInt.
      LocalBuilder myLB1 = myMethodIL.DeclareLocal(typeof(string));
      outputBlock.Text += String.Format("local 'myString' type is: {0}\n", myLB1.LocalType);

      LocalBuilder myLB2 = myMethodIL.DeclareLocal(typeof(int));
      outputBlock.Text += String.Format("local 'myInt' type is: {0}\n", myLB2.LocalType);

      // Store the function argument in myInt.
      myMethodIL.Emit(OpCodes.Ldarg_0);
      myMethodIL.Emit(OpCodes.Stloc_1);

      // Store a literal value in myString, and return the value.
      myMethodIL.Emit(OpCodes.Ldstr, "string value");
      myMethodIL.Emit(OpCodes.Stloc_0);
      myMethodIL.Emit(OpCodes.Ldloc_0);
      myMethodIL.Emit(OpCodes.Ret);

      // Create "Example" class.
      Type myType1 = myTypeBuilder.CreateType();

      // Invoke 'Function1' method of 'Example', passing the value 42.
      Object myObject2 = myType1.InvokeMember("Function1",
          BindingFlags.InvokeMethod, null, null, new Object[] { 42 });

      outputBlock.Text += String.Format("Example.Function1 returned: {0}\n", myObject2);
   }
}
/* This code example produces the following output:

local 'myString' type is: System.String
local 'myInt' type is: System.Int32
Example.Function1 returned: string value
 */