How can I extend two classes the same way without copy-and-paste?

Question

I've written an owner-drawn TabControl, but our project also uses TabWorkspace which derives from TabControl. At the moment, I've got

public class OurTabControl : TabControl
{
     // some code that overrides protected methods
}

public class OurTabWorkspace : TabWorkspace
{
    // the same code
}

I'd like to only have the shared code appear in one place, so we don't have to maintain two copies. Is this possible in C#, and if so, how?

Answer 1

You could do it using an interface and writing an extension method.

class OurTabControl: IBehavior
class OurTabWorkspace: IBehavior

interface IBehavior
{    
}

static class BehaviorExtensions
{
   static [returntype] RepeatedBehavior(this IBehavior behavior)
   {
       //repeated code here
   } 
}

Answer 2

Perhaps refactor the shared code into a single set of static methods?

Answer 3

How about using a partial class? Or, what about defining all the shared methods in one class and have both inherited classes instantiate it.

Answer 4

You could create an internal helper class that contains the common code and reference it as a private member in OurTabControl and OurTabWorkspace. Since TabWorkspace extends TabControl you should be able to take advantage of polymorphism and pass TabControl parameters to methods in the helper class. You would still need to override any common methods in both of your extended classes and call the helper class methods and/or base methods from there.