c# 生成随机N位数字串（每位都不重复）

 /// <summary>

        /// 生成随机数字窜

        /// </summary>

        /// <param name="Digit">位数</param>

        /// <returns></returns>

        private string RandomNum(int Digit)

        {

            ArrayList MyArray = new ArrayList();

            Random random = new Random();

            string str = null;

            int Nums = Digit;

            while (Nums > )

            {

                int i = random.Next(, );// 9>=a>=1

                if (!MyArray.Contains(i))

                {

                    if (MyArray.Count < )

                    {

                        MyArray.Add(i);

                    }

                    Nums -= ;

                }

            }

            for (int j = ; j <= MyArray.Count - ; j++)

            {

                str += MyArray[j].ToString();

            }

            return str;

        }