Question

This question is similar to this one:
Restrict method access to a specific class in C++

However, my question is for C#.

To reiterate: I have two classes, say Foo and Bar which are tightly coupled. Foo exposes a method that I only ever want Bar to have access to.

I kinda have an idea of what I want but no idea how to actually do it, or know if a simpler way exists. It would involve using some kind of attribute that relies on using (new StackFrame(1)).GetMethod().DeclaringType to deny access. Usage would look something like this:

public class Foo {

    [RestrictedUsage(Allow=typeof(Bar))]
    public int SomeMethod() 
    {
        // do something
    }

}

There are probably relevant details I’m missing for the question (I’m new here) – I’ll be sure to update it as I go.

UPDATE:
I should mention that Foo wraps an existing UIElement who’s behavior I am trying to modify. Since the class is sealed, it’s difficult to modify it normally. Bar is the class that transforms the values into the correct values. Bar is non-UI and is used other places in my application. Foo doesn’t know how to transform the value (it’s complex – thats what Bar is for) and that’s why I can’t just wrap the base method.

Jon Skeet gave the answer I was expecting – change the layout of the classes (all thanks be to him so far) but I don’t think either answer is applicable (good answers just not relevant).

I’ve already made mistakes in the code, referencing the wrong property…

Answer 1

Two options:

• Put Foo and Bar in a separate assembly, and make Foo’s method internal
• Make Bar a nested class within Foo, and make the method private

The latter is usually the more practical option, if it’s reasonable to make Bar a nested class.

If neither of these work, I think you’re best off just using an internal method and documenting it – how much do you mistrust the rest of the code in the assembly?