随机生成一组不重复的随机数组

public string RadomNumArray()
        {
            Random r = new Random();
            int a = 0;
            int[] num = new int[6];
            string text = "";
            for (int i = 0; i < 6; i++)
            {//循环生成6个数字
                a = r.Next(0, 99);//随机生成0到99之间的数字
                num[i] = a;
                for (int k = 0; k < num.Length; k++)
                {//遍历数组
                    if (num[i] == num[k] && i != k)
                    {//查找重复重新生成随机数字
                        num[i] = r.Next(0, 99);
                        k = -1;
                    }
                }
                //将数组转换为string类型传参
                if (i == 0)
                    text += num[i];
                else
                    text += "," + num[i];
            }
            return text;
        }
ps:新手一枚，仅供参考，实际功能、优化 有待测试