Question

I have a console application (Host.exe) that is written in Delphi.
I want to redirect the output of the console application in C# application (WinForm).

If I use the following, the (Host.exe) is invoked without problems, but it is not possible to get the output since it is run as (show-window, quite independent).

                ProcessStartInfo pp = new ProcessStartInfo();
                pp.WorkingDirectory = Path.GetDirectoryName(Application.ExecutablePath);
                pp.FileName = Path.Combine(pp.WorkingDirectory, "Host.exe");
                pp.CreateNoWindow = false;
                pp.WindowStyle = ProcessWindowStyle.Normal;
                pp.UseShellExecute = true;
                using (Process pProcess = Process.Start(pp))
                {
                    while ((pProcess != null) && (!pProcess.HasExited))
                    {
                        Application.DoEvents();
                        Thread.Sleep(updatefreq);
                    }
                }

However, if I try to capture the output (redirection), the process will exit immediately (HasExited = true, the loop breaks, the debugger shows, “Only part of a ReadProcessMemory or WriteProcessMemory request was completed”.

                ProcessStartInfo pp = new ProcessStartInfo();
                pp.WorkingDirectory = Path.GetDirectoryName(Application.ExecutablePath);
                pp.FileName = Path.Combine(pp.WorkingDirectory, "Host.exe");
                pp.UseShellExecute = false;
                pp.RedirectStandardOutput = true;
                pp.RedirectStandardInput = true;
                pp.RedirectStandardError = true;
                pp.CreateNoWindow = true;
                pp.WindowStyle = ProcessWindowStyle.Hidden;
                StreamReader outputReader = null;
                using (Process pProcess = Process.Start(pp))
                {
                    if (pProcess != null)
                    {
                        //StreamWriter inputWriter = pProcess.StandardInput;
                        //StreamReader errorReader = pProcess.StandardError;
                        outputReader = pProcess.StandardOutput;
                    }
                    while ((pProcess != null) && (!pProcess.HasExited))
                    {
                        string ss = null;
                        if (outputReader != null)
                        {
                            ss = outputReader.ReadLine();
                        }
                        if ((ss != null) && (2 < ss.Length))
                        {
                            string[] s = ss.Split('|');
                            if (3 == s.Length)
                            {
                                float global;
                                //float.TryParse(s[0], out local);
                                float.TryParse(s[1], out global);
                                RadioTracer.SetCurrentMsg(s[2]);
                                RadioTracer.SetCurrentStep((int)global);
                            }
                        }
                        Application.DoEvents();
                        Thread.Sleep(updatefreq);
                    }
                }

I have googled a lot but haven’t got the solution.
the following pages present similar problems, and I’ve tried the suggested solutions but nothing works.

https://connect.microsoft.com/VisualStudio/feedback/details/609801/unable-to-redirect-only-the-standard-input-of-process-cmd-exe-or-batch-file-from-windows-form-application

http://go4answers.webhost4life.com/Example/redirectstandardinput-a-32-bit-114440.aspx

http://social.msdn.microsoft.com/Forums/en/csharpgeneral/thread/4f946750-6c47-406c-810c-21a2b103b5c4

Thanks a lot… this wastes me a lot of time already.. I hope I can get a solution here.

EDIT: The problem still exists even I don’t use any ReadLine() or ReadToEnd() method. When ‘UseShellExecute’ set to false, the Host.exe will exit immediately.. The Host.exe is supposed to do some big computation (takes around 2 minutes and report progress through console WriteLine every few seconds).

Answer 1

I found out that the following lines will cause errors if you redirect the output in C#. I am using a Console.pas unit in Delphi that in Initialization of that unit, it invokes InitScreenMode procedure.

  Reset(Input);
  Rewrite(Output);
  StdIn := TTextRec(Input).Handle;
  StdOut := TTextRec(Output).Handle;

I am guessing ‘Reset’ or ‘Rewrite’ the Console stdin/stdout will cause problems when ‘UseShellExecute’ set to false in C#