产生固定长度的数字和字母随机数

code

/// <summary>
        /// 产生固定长度的数字和字母随机数
        /// </summary>
        /// <param name="n">生成长度</param>
        /// <returns></returns>
        public static string RandCode(int n)
        {
            char[] arrChar = new char[]{
                'a','b','d','c','e','f','g','h','i','j','k','l','m','n','p','r','q','s','t','u','v','w','z','y','x',
                '0','1','2','3','4','5','6','7','8','9',
                'A','B','C','D','E','F','G','H','I','J','K','L','M','N','Q','P','R','T','S','V','U','W','X','Y','Z'
            };

            StringBuilder num = new StringBuilder();

            Random rnd = new Random(DateTime.Now.Millisecond);
            for (int i = 0; i < n; i++)
            {
                num.Append(arrChar[rnd.Next(0, arrChar.Length)].ToString());
            }

            return num.ToString();
        }

        public static string RandCodeWithNum(int n)
        {
            char[] arrChar = new char[]{
                '0','1','2','3','4','5','6','7','8','9'
            };

            StringBuilder num = new StringBuilder();

            Random rnd = new Random(DateTime.Now.Millisecond);
            for (int i = 0; i < n; i++)
            {
                num.Append(arrChar[rnd.Next(0, arrChar.Length)].ToString());
            }

            return num.ToString();
        }