如何从动态生成的程序集中引用GAC程序集？

AssemblyBuilder ab = AppDomain.CurrentDomain.DefineDynamicAssembly(
    new AssemblyName("MyDynamicAssembly"),
    AssemblyBuilderAccess.RunAndSave);

ModuleBuilder mb = ab.DefineDynamicModule("MyDynamicModule", "MyDynamicAssembly.dll");

TypeBuilder tb = mb.DefineType("MyDynamicType", TypeAttributes.Public);

MethodBuilder methBuilder = tb.DefineMethod("MyDynamicMethod",
    MethodAttributes.Public | MethodAttributes.Static,
    typeof(void),
    Type.EmptyTypes);

ILGenerator il = methBuilder.GetILGenerator();

Type gacType = Type.GetType("GacAssembly.MyNamespace.MyType, GacAssembly, Version=1.0.0.0, Culture=neutral, PublicKeyToken=<your_public_key_token>");
il.Emit(OpCodes.Ldnull);
il.Emit(OpCodes.Call, gacType.GetMethod("MyMethod"));
il.Emit(OpCodes.Ret);

Type dynamicType = tb.CreateType();
ab.Save("MyDynamicAssembly.dll");

Assembly.LoadFrom("MyDynamicAssembly.dll").GetType("MyDynamicType").GetMethod("MyDynamicMethod").Invoke(null, null);