C# 打乱集合

//工具类
private static Random random = new Random();
public static void Shuffle<T>(this IList<T> arr)
{
   var n = arr.Count();
   while (n > 1)
   {
      n--;
      var k = random.Next(0, n + 1);
      var val = arr[k];
      arr[k] = arr[n];
      arr[n] = val;
     }
}
//使用:
List<string> tmpList = new List<string>();
tmpList.Shuffle()