判断是基类的对象还是子类的对象~！！！

Answer 1

if(c is DerivedClass)
  //子类
else
  //父类

Answer 2

public class VirtualInheritSample
    {
        public static void Main()
        {
            DerivedClass c = new DerivedClass();
            c.Call();
        }
    }
    public class BaseClass
    {
        public void A()
        {
            Console.WriteLine("Base A");
        }
        public virtual void B()
        {
            Console.WriteLine("Base B");
        }
    }
    public class DerivedClass : BaseClass
    {
        public new void A()
        {
            Console.WriteLine("Derived A");
        }
        public override void B()
        {
            Console.WriteLine("Derived B");
        }
        public void Call()
        {
            this.A();
            this.B();
            ((BaseClass)this).A();
            ((BaseClass)this).B();
        }
}

Answer 3

方法很多
第一种同2楼if(instance is FatherClass){
}else if(instance is ChildrenClass){
}还有
if（(instance as FatherClass)！=null）{}else if(（instance as ChildrenClass)！=null){}还有
获取对象实例的Type 看看是否equals（typeof(FatherClass)）
等等