C# 生成订单号的几种方式

     public class RandomNumber
     {
         public static object _lock = new object();
         public static int count = ;

         public string GetRandom1()
         {
             lock(_lock)
             {
                 if(count >= )
                 {
                     count = ;
                 }
                 var number = "P" + DateTime.Now.ToString("yyMMddHHmmss") + count.ToString("");
                 count++;
                 return number;
             }
         }

         public string GetRandom2()
         {
             lock(_lock)
             {
                 return "T" + DateTime.Now.Ticks;

             }
         }

         public string GetRandom3()
         {
             lock(_lock)
             {
                 Random ran = new Random();
                 return "U" + DateTime.Now.ToString("yyyyMMddHHmmssfff") + ran.Next(, ).ToString();
             }
         }
     }

调用：

  Response.Write("Number1:"+new RandomNumber().GetRandom1());

  Response.Write("Number2:" + new RandomNumber().GetRandom2());

  Response.Write("Number3:" + new RandomNumber().GetRandom3());

结果： 
Number1:P1608171449140001

Number2:T636070421545568764

Number3:U201608171449145562080