/// 
    /// 将字符串中从n位开始以*代替    /// 
    /// 字符串    /// 开始位置    /// 
         public static string GetPingbStr(string str, int starIndex)    {        string strend = "";        if (str.Length >= starIndex)        {            for (int i = 0; i < str.Length - (starIndex); i++)            {                strend += "*";            }            str = str.Substring(0, starIndex);        }        else            strend = str;        return str + strend;    }