public class OrderInfo
    {
        public OrderState orderState = new NewState();   ///默认新增状态
        
        public OrderInfo(OrderState state)
        {
            orderState = state;
        }
        public void SetPreview()
        {
            if (orderState != null)
            {
                orderState.SetPreviewState(this);
            }
        }
        public void SetNext()
        {
            if (orderState != null)
            {
                orderState.SetNextState(this);
            }
        }
    }
    public abstract class OrderState
    {
        public abstract void SetPreviewState(OrderInfo orderInfo);
        public abstract void SetNextState(OrderInfo orderInfo);
    }
    public class NewState : OrderState
    {

        public override void SetNextState(OrderInfo orderInfo)
        {
            Console.WriteLine("审核成功");
            orderInfo.orderState = new CheckState();

        }
        public override void SetPreviewState(OrderInfo orderInfo)
        {
            ///没有上一个状态了
        }
    }
    public class CheckState : OrderState
    {

        public override void SetNextState(OrderInfo orderInfo)
        {
            Console.WriteLine("审核成功");
            orderInfo.orderState = new NewState();
        }
        public override void SetPreviewState(OrderInfo orderInfo)
        {
            Console.WriteLine("取消审核成功");
            orderInfo.orderState = new NewState();
        }
    }
    public class SummitState : OrderState
    {

        public override void SetNextState(OrderInfo orderInfo)
        {
            Console.WriteLine("订单完成");
            orderInfo.orderState = new CheckState();
        }
        public override void SetPreviewState(OrderInfo orderInfo)
        {
            Console.WriteLine("回退订单成功");
            orderInfo.orderState = new CheckState();
        }
    }
    public class FinishState : OrderState
    {

        public override void SetNextState(OrderInfo orderInfo)
        {
            Console.WriteLine("订单已经结束");
        }
        public override void SetPreviewState(OrderInfo orderInfo)
        {

        }
    }