private AssemblyName _assemblyName;
private AssemblyBuilder _asssemblyBuilder;
private ModuleBuilder _moduleBuilder;
private TypeBuilder _typeBuilder;

// Create the new assembly
_assemblyName = new AssemblyName("ModuleName");
_asssemblyBuilder = AppDomain.CurrentDomain.DefineDynamicAssembly(_assemblyName, AssemblyBuilderAccess.Run);

// Create the default constructor.
ConstructorInfo baseConstructorInfo = typeof(object).GetConstructor(new Type[0]);
ConstructorBuilder constructorBuilder =
      _typeBuilder.DefineConstructor(
                 MethodAttributes.Public,
                 CallingConventions.Standard,
                 Type.EmptyTypes);

// Create the base call operations.
ILGenerator ilGenerator = constructorBuilder.GetILGenerator();

ilGenerator.Emit(?);
ilGenerator.Emit(?);
ilGenerator.Emit(?);
ilGenerator.Emit(OpCodes.Ret);