C# 进程。启动标准输出始终为空

我尝试了在这里和其他地方发布的大量示例，它们应该捕获并输出process.start命令的标准输出。但无论是同步还是异步，输出总是空的

StringBuilder outputBuilder;
ProcessStartInfo processStartInfo;
Process process;

outputBuilder = new StringBuilder();

processStartInfo = new ProcessStartInfo();
processStartInfo.CreateNoWindow = true;
processStartInfo.RedirectStandardOutput = true;
processStartInfo.RedirectStandardInput = true;
processStartInfo.UseShellExecute = false;
processStartInfo.Arguments = "-ss 00:00:50 -t 240 -i Input.MOV -to 00:00:02 -qscale 0 _OUTPUT.MOV";
processStartInfo.FileName = "ffmpeg.exe";

process = new Process();
process.StartInfo = processStartInfo;
// enable raising events because Process does not raise events by default
process.EnableRaisingEvents = true;
// attach the event handler for OutputDataReceived before starting the process
process.OutputDataReceived += new DataReceivedEventHandler
(
    delegate(object sender, DataReceivedEventArgs e)
    {
        // append the new data to the data already read-in
        outputBuilder.Append(e.Data);
    }
);
// start the process
// then begin asynchronously reading the output
// then wait for the process to exit
// then cancel asynchronously reading the output
process.Start();
process.BeginOutputReadLine();
process.WaitForExit();
process.CancelOutputRead();

// use the output
string output = outputBuilder.ToString();

进程按预期执行，但并没有捕获输出，尽管它显示在VSIDE输出窗格中

知道这里出了什么问题吗

---

致意。

谢谢艾米，这是正确的，正常输出由返回

BeginErrorReadLine

---

还可以使用

BeginErrorReadLine

和等效处理程序侦听错误。

delegate（对象发送方，DataReceivedEventArgs e）

这看起来是错误的。只需拆下它以及与之配套的打开/关闭支架。