浅析.net策略模式

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace DesignModel
{
    /// <summary>
    /// 策略模式
    /// </summary>
    public class TacticsModel
    {
        public string type { get; set; }
        public virtual string GetResult()
        {
            return "";
        }
    }
    public class Normal:TacticsModel
    {
        public override string GetResult()
        {
            return "正常计算价格";
        }
    }
    public class Discount : TacticsModel
    {
        public override string GetResult()
        {
            return "按打折计算价格";
        }
    }
    public class Preferential : TacticsModel
    {
        public override string GetResult()
        {
            return "满300减100活动";
        }
    }
    public class CashContext
    {
        TacticsModel tm = null;
        public CashContext(string type)
        {
            switch (type)
            {
                case "1":
                    tm = new Normal();
                    break;
                case "2":
                    tm = new Discount();
                    break;
                case "3":
                    tm = new Preferential();
                    break;
                default:
                break;
             }
        }
        public string GetResult()
        {
            return tm.GetResult();
        }
    }
}

   Console.WriteLine("请计算类型1正常，2打折，3优惠");
   string type = Console.ReadLine();
   CashContext = new CashContext(type);
   Console.WriteLine(.GetResult());