生成随机密码

public string GeneratePassword(int length)        {            StringBuilder password = new StringBuilder();            string chars = "1234567890aAbBcCdDeEfFgGhHiIjJkKlLmMnNoOpPqQrRsStTuUvVwWxXyYzZ";            Random dandom = new Random();            for (int i = 0; i < length; i++)            {                int index = dandom.Next(0, chars.Length);                password.Append(chars[index].ToString());            }            return password.ToString();        }