当使用Switch时 case太多，用委托代替

 switch (_mediaState)
            {
                case State.Run:
                  AAA();
                    break;
                case State.Stop:
                   BBB();
                    break;
                case State.Forward:
                    CCC();
                    break;
                case State.Rewind:
                    DDD();
                    break;
            }             

public delegate void RelaceSwitch();
private  static Dictionary<State,RelaceSwitch> ReplaceSwitch=new Dictionary<State, RelaceSwitch>();

        public static void MethodRun()
        {
            AAA();
        }
        public static void MethodStop()
        {
            BBB();
        }
        public static void MethodForward()
        {
            CCC();
        }
        public static void MethodRewind()
        {
            DDD();
        }


        private static void Adddic()
        {
            ReplaceSwitch.Add(State.Run, MethodRun);//ReplaceSwitch[State.Run]=MethodRun;
            ReplaceSwitch.Add(State.Stop, MethodStop);
            ReplaceSwitch.Add(State.Forward, MethodForward);
            ReplaceSwitch.Add(State.Rewind, MethodRewind);
        }

        private static void Exec(State state, RelaceSwitch action)
        {
            action.Invoke();
        }

调用

去掉switch

首先Adddic();

之后Exec(_mediaState, ReplaceSwitch[_mediaState]);