c#不重复的排序方法

public int getRandom(int num)
{
Thread.Sleep(5);
// Random ro = new Random(unchecked((int)DateTime.Now.Ticks));
Random ro = new Random(System.Guid.NewGuid().GetHashCode());

int iResult;
int iUp = num+1;
int iDown = 1;
iResult = ro.Next(iDown, iUp);
return iResult;
}

public int getRandom(int down,int num)
{
Thread.Sleep(5);
//Random ro = new Random(unchecked((int)DateTime.Now.Ticks));
Random ro = new Random(System.Guid.NewGuid().GetHashCode());
int iResult;
int iUp = num + 1;
int iDown = down;
iResult = ro.Next(iDown, iUp);
return iResult;
}