Problem to save assembly via System.Reflection.Emit.

[C# Programming]

Hi
I've used from this link to define a new simple type and then save to disk with .dll extension via this code :


private void button1_Click(object sender, EventArgs e)
{
AssemblyName asmName = new AssemblyName();
asmName.Name = "HelloWorld";

AssemblyBuilder asmBuilder = Thread.GetDomain().DefineDynamicAssembly(asmName, AssemblyBuilderAccess.RunAndSave);
ModuleBuilder modBuilder = asmBuilder.DefineDynamicModule("HelloWorld");
TypeBuilder typeBuilder = modBuilder.DefineType("Hello", TypeAttributes.Public, typeof(object), new Type[] { typeof(IHello) });

MethodBuilder methodBuilder = typeBuilder.DefineMethod("SayHello", MethodAttributes.Private | MethodAttributes.Virtual, typeof(void), new Type[] { typeof(string) });

typeBuilder.DefineMethodOverride(methodBuilder, typeof(IHello).GetMethod("SayHello"));
ILGenerator il = methodBuilder.GetILGenerator();

// string.Format("Hello, {0} World!", toWhom)
il.Emit(OpCodes.Ldstr, "Hello, {0} World!");
il.Emit(OpCodes.Ldarg_1);
il.Emit(OpCodes.Call, typeof(string).GetMethod("Format", new Type[] { typeof(string), typeof(object) }));

// Console.WriteLine("Hello, World!");
il.Emit(OpCodes.Call, typeof(Console).GetMethod("WriteLine", new Type[] { typeof(string) }));
il.Emit(OpCodes.Ret);

Type type = typeBuilder.CreateType();
IHello hello = (IHello)Activator.CreateInstance(type);

hello.SayHello("Emit");
asmBuilder.Save(asmName.Name + ".dll");
}

it saved my dll on disk, but when i open it via Reflector, it does not have anything! just have a module named 'RefEmit_OnDiskManifestModule'
can anybody help me where is my problem and how to solve it ?
thanks in advance