【转载】#440

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.

 1 public class Cow: IMoo, IMakeMilk
 2 {
 3     public void Moo()
 4     {
 5         // do mooing here
 6     }
 7 
 8     public double Milk()
 9     {
10         // do milking here
11     }
12 }

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

1 Cow bossie = new Cow("Bossie", 12);
2 
3 // Call both IMoo and IMakeMilk methods
4 bossie.Moo();                        // IMoo.Moo
5 double numGallons = bossie.Milk();   // IMakeMilk.Milk

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

1 IMoo mooStuff = bossie;
2 IMakeMilk milkStuff = bossie;
3 
4 mooStuff.Moo();
5 numGallons = milkStuff.Milk();

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