【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.

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", 12);

// 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