.Net Reflection - Calling unexisting methods

Question

Lets say i call method M1 on class A using reflection. The method does not exist.

Is there any way to put a handler on class A that says, "someone is trying to execute method M1"?

Or

Is it possible to add a method dinamically to a class? I want to add a method M1...Mn that always does MyStaticClass.DoAction("M1...Mn");

Something like:

string methodName = "M1".

A.AddMethod(methodname,x => MyStaticClass.DoAction(x));

Thanks

Answer 1

You need the DLR, specifically DynamicObject.TryInvokeMember. Essentially, you override DynamicObject with as many regular members as you want, and then provide TryInvokeMember to handle other method calls at runtime

Answer 2

There is actually a realy easy way to do this in C# 4.0.. dunno what framework you are using.

This should get you an headstart .. but remember you have to declare a bit more just to make your code safe.

class DynamicTester : DynamicObject
{
    public override bool TryInvokeMember(InvokeMemberBinder binder, object[] args, out object result)
    {
        Console.WriteLine("Someone is calling method {0}", binder.Name); result = null; return true;
    }
    public override bool TryGetMember(GetMemberBinder binder, out object result)
    {
        Console.WriteLine("Someone is trying to get attribute {0}", binder.Name); result = null; return true;
    }
    public override bool TrySetMember(SetMemberBinder binder, object value) 
    {
        Console.WriteLine("Someone is trying to set attribute {0} to value {1}", binder.Name, Convert.ToString(value)); return true;
    }
}
class Program
{
    static void Main(string[] args)
    {
        dynamic dt = new DynamicTester();
        dt.A = "Test"; dt.B = 14; dt.date = DateTime.Now;
        var i = dt.Z;
        dt.Tester(1, 2, 3);
    }
}

The key part is to use dynamic as data type. That will mark it not to try to resolve method/attribute calls at compile time but at runtime even with your own code.

simplifies a lot the whole refactoring that had to be done before.