using System;

using System.Reflection;

using System.Reflection.Emit;    

public class Program

{

    public static void Main()

    {

        AssemblyBuilder assemBuilder = AssemblyBuilder.DefineDynamicAssembly(new AssemblyName() { Name = "DynamicAssembly" }, AssemblyBuilderAccess.Run);

        TypeBuilder main_builder = assemBuilder.DefineDynamicModule("DynamicModule").DefineType("Main", TypeAttributes.Public);

​

        TypeBuilder a_builder = main_builder.DefineNestedType("A", TypeAttributes.NestedPublic);

        TypeBuilder b_builder = main_builder.DefineNestedType("B", TypeAttributes.NestedPublic, a_builder);

​

        var a_constr = a_builder.DefineDefaultConstructor(MethodAttributes.Public);

        var b_cnstr = b_builder.DefineConstructor(MethodAttributes.Public, CallingConventions.Standard, Type.EmptyTypes);

​

        {

            //  Creation b constructor    

            var il_gen = b_cnstr.GetILGenerator();

            il_gen.Emit(OpCodes.Ldarg_0);

            il_gen.Emit(OpCodes.Call, a_constr);

            il_gen.Emit(OpCodes.Ret);

        }

​

        main_builder.CreateType();

        a_builder.CreateType();

        b_builder.CreateType();

        Console.WriteLine("done");

    }

}