随机数

    private static char[] constant = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' };
    /// <summary>
    /// 生成随机数 数字和字符
    /// </summary>
    public static string GetRandomStr(int strLength)
    {
        System.Text.StringBuilder newRandom = new System.Text.StringBuilder(10);
        Random rd = new Random();
        for (int i = 0; i < strLength; i++)
        {
            newRandom.Append(constant[rd.Next(10)]);
        }
        return newRandom.ToString();
    }