How to start a process in the background and read standard output

Question

I am new to C#, I have to start a very time consuming process from my C# program of course without bearing the loss of ui freeze, also I want to read the output printed by the program in cmd and at last I want a stop button so that I can close the program whenever I want...

Please help..

Have a look at: https://stackoverflow.com/questions/4291912/process-start-how-to-get-the-output. Also to kill the process you can use Process.Kill() — Paul Sütterlin, Jun 14 '20 at 13:13
But they all are on main ui thread. I have to run a very time consuming process, it will freeze the ui... — Gautam Kumar Giri, Jun 14 '20 at 13:15
The Process itself gets a new thread, but reading from the Output blocks the main thread. To make it async you could start a new Thread which reads from the process Stdout or use the StreamReader.ReadToEndAsync or StreamReader.ReadLineAsync methods. — Paul Sütterlin, Jun 14 '20 at 13:19
There are hundreds of duplicates of this question on this site. Did you try to perform a minimal search? — Pavel Anikhouski, Jun 14 '20 at 13:29
Does this answer your question? [Process.start: how to get the output?](https://stackoverflow.com/questions/4291912/process-start-how-to-get-the-output) — sayah imad, Jun 14 '20 at 13:44

kuso.sama · Answer 1 · 2020-06-14T13:27:33.097

1

try:

using System.Diagnostics;

void startProcess()
{
Process p = new Process();
            p.StartInfo.FileName = "FileName";
            p.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
            p.StartInfo.RedirectStandardOutput = true;
p.StartInfo.UseShellExecute = false;
            p.Start();

            var output = p.StandardOutput.ReadToEnd();
}

MethodInvoker starter = new MethodInvoker(startProcess);

starter.BeginInvoke(null, null);

for ending the process:

p.close()

edited Jun 14 '20 at 13:27

answered Jun 14 '20 at 13:15

kuso.sama

336
1
9

This is on main ui thread, it will freeze the ui... – Gautam Kumar Giri Jun 14 '20 at 13:16
I don't know much I am noob – Gautam Kumar Giri Jun 14 '20 at 13:28
Okk I will try. Thnks – Gautam Kumar Giri Jun 14 '20 at 13:30

score 0 · Answer 2 · answered Jun 14 '20 at 13:31

0

Use something like this:

void StartProcess(){
   Process p = new Process();
   p.StartInfo.FileName = "yourfile.exe";
   p.StartInfo.UseShellExecute = false;
   p.StartInfo.RedirectStandardOutput = true;
   p.Start();
   var readingThread = new System.Threading.Thread(() => {
      while (!p.StandardOutput.EndOfStream){
         Console.WriteLine(p.StandartOutput.ReadLine());
         System.Threading.Thread.Sleep(1);
      }
   }
   readingThread.Start();
}

answered Jun 14 '20 at 13:31

Paul Sütterlin

334
1
6

Can you please explain why are you doing the system.threading.sleep? – Gautam Kumar Giri Jun 14 '20 at 13:33
If you don't use it, the program uses extremly much of your CPU resources (up to 50%). By adding a one millisecond sleep it doesn't take anywhere near this much resources. – Paul Sütterlin Jun 14 '20 at 13:35
OK thnks I will give it a try – Gautam Kumar Giri Jun 14 '20 at 13:36

How to start a process in the background and read standard output

2 Answers2