inherit from two classes in C# [duplicate]

Question

Possible Duplicate:
Multiple Inheritance in C#

I have two classes Class A and Class B. These two classes cannot inherit each other. I am creating new class called Class C. Now, I want to implement the methods in class A and class B by inheriting. I am aware that multiple inheritance is not possible in C# but is there any other way to do this?

Answer 1

Multitiple inheritance is not possible in C#, however it can be simulated using interfaces, see Simulated Multiple Inheritance Pattern for C#.

The basic idea is to define an interface for the members on class B that you wish to access (call it IB), and then have C inherit from A and implement IB by internally storing an instance of B, for example:

class C : A, IB {     private B _b = new B();      // IB members     public void SomeMethod()     {         _b.SomeMethod();     } } 

There are also a couple of other alternaitve patterns explained on that page.

Answer 2

An common alternative to inheritance is delegation (also called composition): X "has a" Y rather than X "is a" Y. So if A has functionality for dealing with Foos, and B has functionality for dealing with Bars, and you want both in C, then something like this:

public class A() {   private FooManager fooManager = new FooManager(); // (or inject, if you have IoC)    public void handleFoo(Foo foo) {     fooManager.handleFoo(foo);   } }  public class B() {   private BarManager barManager = new BarManager(); // (or inject, if you have IoC)    public void handleBar(Bar bar) {     barManager.handleBar(bar);   } }  public class C() {   private FooManager fooManager = new FooManager(); // (or inject, if you have IoC)   private BarManager barManager = new BarManager(); // (or inject, if you have IoC)    ... etc }