接口例子[转]

public interface  ISpeak
{
    void Speak();
}

public Cat:ISpeak
{
    public override void Speak()
    {
         Say("喵~~~");
    }
}

public Dog:ISpeak
{
    public override void Speak()
    {
         Say("汪汪！");
    }
}

public LZ:ISpeak
{
    public override void Speak()
    {
         Say("靠！管我屁事！");
    }
}

比如有一个ArrayList arrSpeak，存储许多能“说话”的生物吗，
我们就可以这样调用
foreach(object obj in arrSpeak)  //实现基类中调用派生类功能
{
    ISpeak speak = obj as ISpeak;
    speak.Speak();
}