Why Does ProcessStartInfo.WaitForExit() Stall When Redirecting StandardOutput or StandardError?

solve the problem that the processstartInfo.WaitForexit () is stuck when the regattcing output or standard error of the standard

When the ProcessStartInfo redirects to StandardoutPut or Standarderror, there may be problems. The internal buffer may overflow, leading to a potential deadlocked or blocking your process.

In order to prevent such deadlocks and collect output from two streams, consider using the following asynchronous reading methods:

This asynchronous method ensures that the buffer will not overflow and prevent the system from freezing. Now you can read and collect output without worrying about delayed or potential dead locks. The code has been improved and includes the processing of error output.

using System.Diagnostics;
using System.Text;
using System.Threading;

class Program
{
    static void Main(string[] args)
    {
        string filename = "TheProgram.exe";
        string arguments = "some arguments";
        int timeout = 10000; // 10 秒超时

        using (Process process = new Process())
        {
            process.StartInfo.FileName = filename;
            process.StartInfo.Arguments = arguments;
            process.StartInfo.UseShellExecute = false;
            process.StartInfo.RedirectStandardOutput = true;
            process.StartInfo.RedirectStandardError = true;

            StringBuilder output = new StringBuilder();
            StringBuilder error = new StringBuilder();

            using (AutoResetEvent outputWaitHandle = new AutoResetEvent(false))
            using (AutoResetEvent errorWaitHandle = new AutoResetEvent(false))
            {
                process.OutputDataReceived += (sender, e) =>
                {
                    if (e.Data == null)
                    {
                        outputWaitHandle.Set();
                    }
                    else
                    {
                        output.AppendLine(e.Data);
                    }
                };
                process.ErrorDataReceived += (sender, e) =>
                {
                    if (e.Data == null)
                    {
                        errorWaitHandle.Set();
                    }
                    else
                    {
                        error.AppendLine(e.Data);
                    }
                };

                process.Start();
                process.BeginOutputReadLine();
                process.BeginErrorReadLine();

                if (process.WaitForExit(timeout) &&
                    outputWaitHandle.WaitOne(timeout) &&
                    errorWaitHandle.WaitOne(timeout))
                {
                    // 进程成功完成。在此处检查 process.ExitCode。
                    Console.WriteLine($"输出: {output}");
                    Console.WriteLine($"错误: {error}"); //添加错误输出
                }
                else
                {
                    // 超时或发生错误。
                    Console.WriteLine("进程超时或失败。");
                }
            }
        }
    }
}

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