C# sealed 方法

sealed是用来中断继承链的。

sealed 能让一个类失去被继承的能力。

public class SubClass : BaseInterClass {        public override void absfunction()        {            base.absfunction();            Console.WriteLine("beside baseclass ovveride absfunction output, sub class override absfunction!!!");        }           }    sealed class subsubClass : SubClass { }    class subsubsubClass : SubClass { }

sealed用在方法上就是 到当前类为止，所有继承当前类的子类都无法再override这个方法了。

1. virtual / abstract 类型的方法必须是public的。
2. abstract类型的方法只能定义在abstract类中，virtual类型的方法无限制。
   
3. 只有virtual / abstract 类型的方法才能被override.
4. virtual 类型的方法可以有具体实现。
5. abstract 类型的方法不可以有具体实现，只能有定义。
   

public abstract class AbstractClass{        static void show() { Console.WriteLine("abstractor class show function !!!"); }        public virtual void hello() { Console.WriteLine("abs class hello function !!!"); }        public abstract void absfunction();        public void normalfunction() { Console.WriteLine("abs class normal function!!!"); }            }    public class BaseInterClass : AbstractClass    {        public sealed override void hello() { Console.WriteLine("abs class sealed hello function,avoid be overitten!!!!"); }        public override void absfunction()        {            Console.WriteLine("BaseInterClass override function!!!");        }            }    public class SubClass : BaseInterClass {        public override void absfunction()        {            base.absfunction();            Console.WriteLine("beside baseclass ovveride absfunction output, sub class override absfunction!!!");        }    }调用：BaseInterClass b1 = new BaseInterClass();            b1.normalfunction();            b1.hello();            SubClass b2 = new SubClass();            b2.hello();            b2.absfunction();输出：base class normal function!!!abs class normal function!!!abs class sealed hello function,avoid be overitten!!!!abs class sealed hello function,avoid be overitten!!!!BaseInterClass override function!!!beside baseclass ovveride absfunction output, sub class override absfunction!!!