net use连不上


            string strLogoOn = "net use " + toDirectory + " /user:" + strUserName + " " + strPassword;            Process p_Tmp = new Process();
            p_Tmp.StartInfo.RedirectStandardError = true;
            p_Tmp.StartInfo.RedirectStandardInput = true;
            p_Tmp.StartInfo.RedirectStandardOutput = true;
            p_Tmp.StartInfo.UseShellExecute = false;
            p_Tmp.StartInfo.CreateNoWindow = true;
            p_Tmp.StartInfo.FileName = "cmd.exe";
            p_Tmp.Start();
            p_Tmp.StandardInput.WriteLine(strLogoOn);
            p_Tmp.StandardInput.WriteLine("exit");
            p_Tmp.Close();
            p_Tmp.Dispose(); 通过调试，strLogoOn的值复制到cmd里面可以连接成功，可是通过.NET程序却运行不成功？帮忙看看吧。