一个生成不重复随机数的方法

//生成不重复随机数算法 private int GetRandomNum(int i,int length,int up,int down) {  int iFirst=0;  Random ro=new Random(i*length*unchecked((int)DateTime.Now.Ticks));  iFirst=ro.Next(up,down);  return iFirst; }

 

//这种办法更保险

private string GetRandomNum() {             Random ro = new Random(Guid.NewGuid().GetHashCode());             string iFirst = ro.Next(10, 99).ToString();             return iFirst;  }