【转载】#440 - A Class Can Implement More than One Interface

It's possible for a class to implement more than one interface.

For example, a Cow class might implement both the IMoo and the IMakeMilk interfaces. Multiple interfaces are listed after the class declaration, separated by commas.

 public class Cow: IMoo, IMakeMilk
 {
     public void Moo()
     {
         // do mooing here
     }

     public double Milk()
     {
         // do milking here
     }
 }     

You can now use an instance of the Cow class to access members of either interface.

 Cow bossie = new Cow("Bossie", );

 // Call both IMoo and IMakeMilk methods
 bossie.Moo();                        // IMoo.Moo
 double numGallons = bossie.Milk();   // IMakeMilk.Milk

We can also set interface variables of either interface type to an instance of a Cow.

 IMoo mooStuff = bossie;
 IMakeMilk milkStuff = bossie;

 mooStuff.Moo();
 numGallons = milkStuff.Milk();

原文地址：#440 - A Class Can Implement More than One Interface