Question

我需要生成一个作为控制台应用程序的子进程，并捕获其输出。

我为方法编写了以下代码：

string retMessage = String.Empty;
ProcessStartInfo startInfo = new ProcessStartInfo();
Process p = new Process();

startInfo.CreateNoWindow = true;
startInfo.RedirectStandardOutput = true;
startInfo.RedirectStandardInput = true;

startInfo.UseShellExecute = false;
startInfo.Arguments = command;
startInfo.FileName = exec;

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

p.OutputDataReceived += new DataReceivedEventHandler
(
    delegate(object sender, DataReceivedEventArgs e)
    {
        using (StreamReader output = p.StandardOutput)
        {
            retMessage = output.ReadToEnd();
        }
    }
);

p.WaitForExit();

return retMessage;

但是，这不会返回任何内容。我不相信OutputDataReceived事件被回调，或WaitForExit()命令可能阻塞线程，因此它永远不会回调。

有什么建议吗？

编辑：看起来我在回调时太努力了。这样做的：

return p.StandardOutput.ReadToEnd();

似乎工作正常。

Answer 1

这是我已经验证可以使用的代码。我用它来产生MSBuild并听取它的输出：

process.StartInfo.UseShellExecute = false;
process.StartInfo.RedirectStandardOutput = true;
process.OutputDataReceived += (sender, args) => Console.WriteLine("received output: {0}", args.Data);
process.Start();
process.BeginOutputReadLine();

Answer 2

我刚尝试了这件事，以下内容对我有用：

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 = "<insert command line arguments here>";
processStartInfo.FileName = "<insert tool path here>";

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();

Answer 3

我需要捕获stdout和stderr，并且如果进程在预期时没有退出，则将其超时。我想出了这个：

Process process = new Process();
StringBuilder outputStringBuilder = new StringBuilder();

try
{
process.StartInfo.FileName = exeFileName;
process.StartInfo.WorkingDirectory = args.ExeDirectory;
process.StartInfo.Arguments = args;
process.StartInfo.RedirectStandardError = true;
process.StartInfo.RedirectStandardOutput = true;
process.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
process.StartInfo.CreateNoWindow = true;
process.StartInfo.UseShellExecute = false;
process.EnableRaisingEvents = false;
process.OutputDataReceived += (sender, eventArgs) => outputStringBuilder.AppendLine(eventArgs.Data);
process.ErrorDataReceived += (sender, eventArgs) => outputStringBuilder.AppendLine(eventArgs.Data);
process.Start();
process.BeginOutputReadLine();
process.BeginErrorReadLine();
var processExited = process.WaitForExit(PROCESS_TIMEOUT);

if (processExited == false) // we timed out...
{
    process.Kill();
    throw new Exception("ERROR: Process took too long to finish");
}
else if (process.ExitCode != 0)
{
    var output = outputStringBuilder.ToString();
    var prefixMessage = "";

    throw new Exception("Process exited with non-zero exit code of: " + process.ExitCode + Environment.NewLine + 
    "Output from process: " + outputStringBuilder.ToString());
}
}
finally
{                
process.Close();
}

我将stdout和stderr连接到同一个字符串中，但如果需要，可以将它分开。它使用事件，所以它应该处理它们（我相信）。我已成功运行，并将很快进行批量测试。

Answer 4

看起来你的两条线路无序。您在设置事件处理程序以捕获输出之前启动该过程。在添加事件处理程序之前，该过程可能刚刚完成。

像这样切换线条。

p.OutputDataReceived += ...
p.Start();

Answer 5

这里有一些完整而简单的代码。我使用它时工作正常。

var processStartInfo = new ProcessStartInfo
{
    FileName = @"C:\SomeProgram",
    Arguments = "Arguments",
    RedirectStandardOutput = true,
    UseShellExecute = false
};
var process = Process.Start(processStartInfo);
var output = process.StandardOutput.ReadToEnd();
process.WaitForExit();

请注意，这仅捕获标准输出;它不会捕获标准的错误。如果您想要两者，请为每个流使用this technique。

Answer 6

设置StartInfo后，需要调用p.Start（）来实际运行该进程。实际上，您的函数可能挂在WaitForExit（）调用上，因为该进程实际上从未启动过。

Answer 7

重定向流是异步的，并且可能在进程终止后继续。 Umar提及在流程终止后取消process.CancelOutputRead()。然而，这有可能造成数据丢失。

这对我来说是可靠的：

process.WaitForExit(...);
...
while (process.StandardOutput.EndOfStream == false)
{
    Thread.Sleep(100);
}

我没有尝试这种方法，但我喜欢Sly的建议：

if (process.WaitForExit(timeout))
{
    process.WaitForExit();
}

Answer 8

犹大的回答对我不起作用（或者不完整），因为申请在第一次BeginOutputReadLine();之后退出

这对我来说是一个完整的片段，读取ping的常量输出：

        var process = new Process();
        process.StartInfo.FileName = "ping";
        process.StartInfo.Arguments = "google.com -t";
        process.StartInfo.RedirectStandardOutput = true;
        process.StartInfo.UseShellExecute = false;
        process.OutputDataReceived += (sender, a) => Console.WriteLine(a.Data);
        process.Start();
        process.BeginOutputReadLine();
        process.WaitForExit();

Answer 9

这是我用来运行进程并获取其输出和错误的方法：

public static string ShellExecute(this string path, string command, TextWriter writer, params string[] arguments)
    {
        using (var process = Process.Start(new ProcessStartInfo { WorkingDirectory = path, FileName = command, Arguments = string.Join(" ", arguments), UseShellExecute = false, RedirectStandardOutput = true, RedirectStandardError = true }))
        {
            using (process.StandardOutput)
            {
                writer.WriteLine(process.StandardOutput.ReadToEnd());
            }
            using (process.StandardError)
            {
                writer.WriteLine(process.StandardError.ReadToEnd());
            }
        }

        return path;
    }

例如：

@"E:\Temp\MyWorkingDirectory".ShellExecute(@"C:\Program Files\Microsoft SDKs\Windows\v6.0A\Bin\svcutil.exe", Console.Out);

如何在.NET中生成进程并捕获其STDOUT？

9 个答案: