Create a MustOverride Property with Reflection?

Question

Can anyone tell me how I would create a MustOverride property using Reflection?

Answer 1

Do you mean CodeDOM? Reflection is used to read existing code, not create new code.

If you do mean CodeDOM, I believe you just need to create the CodeMemberProperty and set its Attributes property to include MemberAttributes.Abstract.

Answer 2

Do you mean with Reflection.Emit? If so, you use TypeBuilder.DefineMethod, with MethodAttributes.Abstract.

Here's an example; in Bar.Method is abstract; Bar2.Method overrides it.

    AssemblyName an = new AssemblyName("Foo");
    var asm = AppDomain.CurrentDomain.DefineDynamicAssembly(an, AssemblyBuilderAccess.Run);
    var module = asm.DefineDynamicModule("Foo");
    var type = module.DefineType("Bar", TypeAttributes.Abstract | TypeAttributes.Class | TypeAttributes.AnsiClass);
    var method = type.DefineMethod("Method", MethodAttributes.Abstract | MethodAttributes.Public | MethodAttributes.Virtual,
        CallingConventions.HasThis, typeof(int), Type.EmptyTypes);

    var final = type.CreateType();

    type = module.DefineType("Bar2", TypeAttributes.Sealed | TypeAttributes.Class | TypeAttributes.AnsiClass, final);
    var method2 = type.DefineMethod("Bar", MethodAttributes.Public | MethodAttributes.Virtual,
        CallingConventions.HasThis, typeof(int), Type.EmptyTypes);
    var il = method2.GetILGenerator();
    il.Emit(OpCodes.Ldc_I4_4);
    il.Emit(OpCodes.Ret);
    type.DefineMethodOverride(method2, method);

    var concrete = type.CreateType();
    object obj = Activator.CreateInstance(concrete);
    int result = (int) concrete.GetMethod("Bar").Invoke(obj, null);