C#命令行重定向

private static string CreatePdf(string fileName){
    string command = "gswin32c -q -dNOPAUSE -sDEVICE=pdfwrite -sOutputFile=\"" + 
            fileName + ".pdf\"  -fc:\\output.ps";

    Console.WriteLine(command);
    Process p = new Process();

    StreamWriter sw;
    StreamReader sr;

    ProcessStartInfo info = new ProcessStartInfo("cmd");
    info.WorkingDirectory = System.AppDomain.CurrentDomain.BaseDirectory;
    Console.WriteLine("Current directory: " + info.WorkingDirectory);
    info.CreateNoWindow = true;
    info.UseShellExecute = false;

    info.RedirectStandardInput = true;
    info.RedirectStandardOutput = true;

    p.StartInfo = info;
    p.Start();

    sw = p.StandardInput;
    sr = p.StandardOutput;
    sw.AutoFlush = true;

    sw.WriteLine(command);

    sw.Close();

    string ret = sr.ReadToEnd();

    Console.WriteLine(ret);
    return ret;
}