Launching and watching a application for termination? c#

Question

Wondering if you could help me?

I have a application(app1) that can launch another application(app2), whilst app2 is runnning app1 is able to do some mointoring on folder/files that change during the life cycle of app2. I can do this fine and runs perfect.

However I was wondering if there any way that I can monitor app2 to see when it has been terminated so that I can tell app1 one to stop tracking?

I don't have the source code for app2 so I am unable to edit it to send a signal to app1.

Thanks for your time.

Matt

look at [this thread](http://stackoverflow.com/questions/470256/process-waitforexit-asynchronously/470288) — Navid Rahmani, Jun 19 '11 at 21:16

Ivan Danilov · Answer 1 · 2011-06-19T21:11:11.780

2

You could do it like that:

var p = Process.Start("app2.exe");
// do start watching here
p.WaitForExit();
// do stop watching here

Note that it is not production-quality code because if app2 will hang - this code will wait for it forever. There's overload that allows to specify timeout thus you could finish waiting beforehand.

Or alternatively use Process.Exited event as Navid suggested.

edited Jun 19 '11 at 21:11

answered Jun 19 '11 at 21:05

Ivan Danilov

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This does look like a good soloution can I ask though, what benifits this has over Navid's suggestion?(and vise versa?) Thanks – Matthew Deloughry Jun 19 '11 at 21:12
Well, waiting for a process with `WaitForExit` holds your thread busy, so you can't do anything else. If you watching has asynchronous nature like getting notifications called on thread pool threads by the OS - it is ok. On the contrary if you have some UI and can't take its thread (because UI will be 'Not responding' while the UI thread is busy) - event is more suitable. – Ivan Danilov Jun 19 '11 at 21:17
This is synchronous and straight-forward. The other method frees doesn't tie up your application while the other one runs. – Brad Bruce Jun 19 '11 at 21:19

Navid Rahmani · Accepted Answer · 2011-06-19T21:32:59.070

2

If you are using Process use Process.Exited event

Consider this event can occur only if EnableRaisingEvents property is true

Edit: If you need the output of the app2 @Ivan's answer is better you need to wait for exit.

edited Jun 19 '11 at 21:32

answered Jun 19 '11 at 21:07

Navid Rahmani

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If you're using OutputDataReceived and ErrorDataReceived handlers, you can get output using this method. – Brad Bruce Jun 19 '11 at 22:58

score 0 · Answer 3 · answered Jun 19 '11 at 23:17

This is what I've used on a few projects without any issues (so far).

using System.Diagnostics;
using System;

namespace [whatever]
{
    class Executor {
        public event EventHandler Completed;
        public event DataReceivedEventHandler DataReceived;
        public event DataReceivedEventHandler ErrorReceived;

        public void callExecutable(string executable, string args, string workingDir){
            string commandLine = executable;
            ProcessStartInfo psi = new ProcessStartInfo(commandLine);
            psi.UseShellExecute = false;
            psi.LoadUserProfile = false;
            psi.RedirectStandardOutput = true;
            psi.RedirectStandardError = true;
            psi.WindowStyle = ProcessWindowStyle.Minimized;
            psi.CreateNoWindow = true;
            psi.Arguments = args;
            psi.WorkingDirectory = System.IO.Path.GetDirectoryName(executable);
            psi.WorkingDirectory = workingDir;
            Process p = new Process();
            p.StartInfo = psi;
            try{
                p.EnableRaisingEvents = true;
                p.Start();
                if (DataReceived != null) p.OutputDataReceived += DataReceived;
                if (ErrorReceived != null) p.ErrorDataReceived += ErrorReceived;
                p.BeginOutputReadLine();
                p.BeginErrorReadLine();
                p.Exited += new EventHandler(p_Exited);
            }
            catch (Exception ex){
                //log.Error(ex.Message);
            }
        }

        void p_Exited(object sender, EventArgs e) {
            (sender as Process).Close();
            (sender as Process).Dispose();
            if (Completed != null) {
                Completed(this, e);
            }
        }
    }
}
/*
    //In another class
        private void CallProgram() {
            Executor exec = new Executor();
            exec.Completed += new EventHandler(exec_Completed);
            exec.DataReceived += new System.Diagnostics.DataReceivedEventHandler(exec_DataReceived);
            exec.ErrorReceived += new System.Diagnostics.DataReceivedEventHandler(exec_ErrorReceived);
            exec.callExecutable([Program Name],
                [Arguments],
                [Working Dir]);
        }

        void exec_Completed(object sender, EventArgs e) {
            MessageBox.Show("Finshed");
        }

        void exec_DataReceived(object sender, System.Diagnostics.DataReceivedEventArgs e) {
            if (e.Data != null) {
                AddText(e.Data.ToString());
            }
        }

        void exec_ErrorReceived(object sender, System.Diagnostics.DataReceivedEventArgs e) {
            if (e.Data != null) {
                AddText(e.Data.ToString());
            }
        }

        // this handles the cross-thread updating of a winforms control
        private void AddText(string textToAdd) {
            if (textBox1.InvokeRequired) {
                BeginInvoke((MethodInvoker)delegate() { AddText(textToAdd); });
            }
            else {
                textBox1.AppendText(textToAdd);
                textBox1.AppendText("\r\n");
                textBox1.Refresh();
            }
        }

*/

Launching and watching a application for termination? c#

3 Answers3