我有以下代码:

info = new System.Diagnostics.ProcessStartInfo("TheProgram.exe", String.Join(" ", args));
info.CreateNoWindow = true;
info.WindowStyle = System.Diagnostics.ProcessWindowStyle.Hidden;
info.RedirectStandardOutput = true;
info.UseShellExecute = false;
System.Diagnostics.Process p = System.Diagnostics.Process.Start(info);
p.WaitForExit();
Console.WriteLine(p.StandardOutput.ReadToEnd()); //need the StandardOutput contents

我知道我正在启动的进程的输出大约有7MB长。在Windows控制台中运行它可以正常工作。不幸的是,从编程的角度来看,它会无限期地挂在WaitForExit上。还要注意,对于较小的输出(比如3KB),这段代码不会挂起。

ProcessStartInfo中的内部StandardOutput是否可能不能缓冲7MB?如果是,我该怎么办?如果不是,我做错了什么?


当前回答

我认为这是一个简单和更好的方法(我们不需要AutoResetEvent):

public static string GGSCIShell(string Path, string Command)
{
    using (Process process = new Process())
    {
        process.StartInfo.WorkingDirectory = Path;
        process.StartInfo.FileName = Path + @"\ggsci.exe";
        process.StartInfo.CreateNoWindow = true;
        process.StartInfo.RedirectStandardOutput = true;
        process.StartInfo.RedirectStandardInput = true;
        process.StartInfo.UseShellExecute = false;

        StringBuilder output = new StringBuilder();
        process.OutputDataReceived += (sender, e) =>
        {
            if (e.Data != null)
            {
                output.AppendLine(e.Data);
            }
        };

        process.Start();
        process.StandardInput.WriteLine(Command);
        process.BeginOutputReadLine();


        int timeoutParts = 10;
        int timeoutPart = (int)TIMEOUT / timeoutParts;
        do
        {
            Thread.Sleep(500);//sometimes halv scond is enough to empty output buff (therefore "exit" will be accepted without "timeoutPart" waiting)
            process.StandardInput.WriteLine("exit");
            timeoutParts--;
        }
        while (!process.WaitForExit(timeoutPart) && timeoutParts > 0);

        if (timeoutParts <= 0)
        {
            output.AppendLine("------ GGSCIShell TIMEOUT: " + TIMEOUT + "ms ------");
        }

        string result = output.ToString();
        return result;
    }
}

其他回答

https://stackoverflow.com/a/17600012/4151626的信用归于EM0

我的应用程序的其他解决方案(包括EM0)仍然处于死锁状态,这是由于内部超时以及派生应用程序同时使用StandardOutput和standderror。以下是对我有效的方法:

Process p = new Process()
{
  StartInfo = new ProcessStartInfo()
  {
    FileName = exe,
    Arguments = args,
    UseShellExecute = false,
    RedirectStandardOutput = true,
    RedirectStandardError = true
  }
};
p.Start();

string cv_error = null;
Thread et = new Thread(() => { cv_error = p.StandardError.ReadToEnd(); });
et.Start();

string cv_out = null;
Thread ot = new Thread(() => { cv_out = p.StandardOutput.ReadToEnd(); });
ot.Start();

p.WaitForExit();
ot.Join();
et.Join();

编辑:添加初始化StartInfo代码示例

这是一个更现代的可等待的、基于任务并行库(TPL)的。net 4.5及以上版本的解决方案。

使用的例子

try
{
    var exitCode = await StartProcess(
        "dotnet", 
        "--version", 
        @"C:\",
        10000, 
        Console.Out, 
        Console.Out);
    Console.WriteLine($"Process Exited with Exit Code {exitCode}!");
}
catch (TaskCanceledException)
{
    Console.WriteLine("Process Timed Out!");
}

实现

public static async Task<int> StartProcess(
    string filename,
    string arguments,
    string workingDirectory= null,
    int? timeout = null,
    TextWriter outputTextWriter = null,
    TextWriter errorTextWriter = null)
{
    using (var process = new Process()
    {
        StartInfo = new ProcessStartInfo()
        {
            CreateNoWindow = true,
            Arguments = arguments,
            FileName = filename,
            RedirectStandardOutput = outputTextWriter != null,
            RedirectStandardError = errorTextWriter != null,
            UseShellExecute = false,
            WorkingDirectory = workingDirectory
        }
    })
    {
        var cancellationTokenSource = timeout.HasValue ?
            new CancellationTokenSource(timeout.Value) :
            new CancellationTokenSource();

        process.Start();

        var tasks = new List<Task>(3) { process.WaitForExitAsync(cancellationTokenSource.Token) };
        if (outputTextWriter != null)
        {
            tasks.Add(ReadAsync(
                x =>
                {
                    process.OutputDataReceived += x;
                    process.BeginOutputReadLine();
                },
                x => process.OutputDataReceived -= x,
                outputTextWriter,
                cancellationTokenSource.Token));
        }

        if (errorTextWriter != null)
        {
            tasks.Add(ReadAsync(
                x =>
                {
                    process.ErrorDataReceived += x;
                    process.BeginErrorReadLine();
                },
                x => process.ErrorDataReceived -= x,
                errorTextWriter,
                cancellationTokenSource.Token));
        }

        await Task.WhenAll(tasks);
        return process.ExitCode;
    }
}

/// <summary>
/// Waits asynchronously for the process to exit.
/// </summary>
/// <param name="process">The process to wait for cancellation.</param>
/// <param name="cancellationToken">A cancellation token. If invoked, the task will return
/// immediately as cancelled.</param>
/// <returns>A Task representing waiting for the process to end.</returns>
public static Task WaitForExitAsync(
    this Process process,
    CancellationToken cancellationToken = default(CancellationToken))
{
    process.EnableRaisingEvents = true;

    var taskCompletionSource = new TaskCompletionSource<object>();

    EventHandler handler = null;
    handler = (sender, args) =>
    {
        process.Exited -= handler;
        taskCompletionSource.TrySetResult(null);
    };
    process.Exited += handler;

    if (cancellationToken != default(CancellationToken))
    {
        cancellationToken.Register(
            () =>
            {
                process.Exited -= handler;
                taskCompletionSource.TrySetCanceled();
            });
    }

    return taskCompletionSource.Task;
}

/// <summary>
/// Reads the data from the specified data recieved event and writes it to the
/// <paramref name="textWriter"/>.
/// </summary>
/// <param name="addHandler">Adds the event handler.</param>
/// <param name="removeHandler">Removes the event handler.</param>
/// <param name="textWriter">The text writer.</param>
/// <param name="cancellationToken">The cancellation token.</param>
/// <returns>A task representing the asynchronous operation.</returns>
public static Task ReadAsync(
    this Action<DataReceivedEventHandler> addHandler,
    Action<DataReceivedEventHandler> removeHandler,
    TextWriter textWriter,
    CancellationToken cancellationToken = default(CancellationToken))
{
    var taskCompletionSource = new TaskCompletionSource<object>();

    DataReceivedEventHandler handler = null;
    handler = new DataReceivedEventHandler(
        (sender, e) =>
        {
            if (e.Data == null)
            {
                removeHandler(handler);
                taskCompletionSource.TrySetResult(null);
            }
            else
            {
                textWriter.WriteLine(e.Data);
            }
        });

    addHandler(handler);

    if (cancellationToken != default(CancellationToken))
    {
        cancellationToken.Register(
            () =>
            {
                removeHandler(handler);
                taskCompletionSource.TrySetCanceled();
            });
    }

    return taskCompletionSource.Task;
}

我知道这是晚餐,但是,在读完这一整页后,没有一个解决方案对我来说是有效的,尽管我没有尝试Muhammad Rehan,因为代码有点难理解,尽管我猜他是在正确的轨道上。当我说它不工作时,这并不完全正确,有时它会工作得很好,我猜这与EOF标记之前的输出长度有关。

不管怎样,对我来说有效的解决方案是使用不同的线程来读取StandardOutput和StandardError并写入消息。

        StreamWriter sw = null;
        var queue = new ConcurrentQueue<string>();

        var flushTask = new System.Timers.Timer(50);
        flushTask.Elapsed += (s, e) =>
        {
            while (!queue.IsEmpty)
            {
                string line = null;
                if (queue.TryDequeue(out line))
                    sw.WriteLine(line);
            }
            sw.FlushAsync();
        };
        flushTask.Start();

        using (var process = new Process())
        {
            try
            {
                process.StartInfo.FileName = @"...";
                process.StartInfo.Arguments = $"...";
                process.StartInfo.UseShellExecute = false;
                process.StartInfo.RedirectStandardOutput = true;
                process.StartInfo.RedirectStandardError = true;

                process.Start();

                var outputRead = Task.Run(() =>
                {
                    while (!process.StandardOutput.EndOfStream)
                    {
                        queue.Enqueue(process.StandardOutput.ReadLine());
                    }
                });

                var errorRead = Task.Run(() =>
                {
                    while (!process.StandardError.EndOfStream)
                    {
                        queue.Enqueue(process.StandardError.ReadLine());
                    }
                });

                var timeout = new TimeSpan(hours: 0, minutes: 10, seconds: 0);

                if (Task.WaitAll(new[] { outputRead, errorRead }, timeout) &&
                    process.WaitForExit((int)timeout.TotalMilliseconds))
                {
                    if (process.ExitCode != 0)
                    {
                        throw new Exception($"Failed run... blah blah");
                    }
                }
                else
                {
                    throw new Exception($"process timed out after waiting {timeout}");
                }
            }
            catch (Exception e)
            {
                throw new Exception($"Failed to succesfully run the process.....", e);
            }
        }
    }

希望这能帮助那些认为这很难的人!

我们也有这个问题(或一个变体)。

试试下面的方法:

1)为p.WaitForExit(nnnn)添加超时;其中NNNN以毫秒为单位。

2)将ReadToEnd调用放在WaitForExit调用之前。这是我们看到MS推荐的。

上面的答案没有一个能起作用。

Rob解决方案挂起,“Mark Byers”解决方案获得已处理异常。(我尝试了其他答案的“解决方案”)。

所以我决定提出另一个解决方案:

public void GetProcessOutputWithTimeout(Process process, int timeoutSec, CancellationToken token, out string output, out int exitCode)
{
    string outputLocal = "";  int localExitCode = -1;
    var task = System.Threading.Tasks.Task.Factory.StartNew(() =>
    {
        outputLocal = process.StandardOutput.ReadToEnd();
        process.WaitForExit();
        localExitCode = process.ExitCode;
    }, token);

    if (task.Wait(timeoutSec, token))
    {
        output = outputLocal;
        exitCode = localExitCode;
    }
    else
    {
        exitCode = -1;
        output = "";
    }
}

using (var process = new Process())
{
    process.StartInfo = ...;
    process.Start();
    string outputUnicode; int exitCode;
    GetProcessOutputWithTimeout(process, PROCESS_TIMEOUT, out outputUnicode, out exitCode);
}

这段代码经过调试,工作完美。