Canceling a Process started via System.Diagnostics.Process.Start()

c#

Solution

For cooperative cancellation, you need to listen to BackgroundWorker.CancellationPending in BackgroundWorker.DoWork event.

How to: Use a Background Worker

private void worker_DoWork(object sender, DoWorkEventArgs e)
{
    using (var process = new Process())
    {
        //...

        process.Start()

        //...
        while(true)
        { 
            if ((sender as BackgroundWorker).CancellationPending && !process.HasExited)
            {
              process.Kill();
              break;
            }
            Thread.Sleep(100);
         }

        process.WaitForExit();
    }
}

Problem

I am writing an application where I have a Process running in a `BackgroundWorker`. I would like to support cancellation from the user interface, but I don't see an easy way to do this. The `Process` is actually a fairly long running command line exe. The output is getting redirected asynchronously via the `Progress.OutputDataReceived` event and is being used to report progress to the GUI. ``` private void worker_DoWork(object sender, DoWorkEventArgs e) { using (var process = new Process()) { //... process.Start() //... process.WaitForExit(); } } private void CancelWorker() { worker.CancelAsync(); // where to actually listen for the cancellation??? } ``` There doesn't appear to be a way to have the process "listen" for any input from the main thread aside from the `StandardInput`, but that won't work unless the app itself will response to a specific input to abort. Is there a way to cancel a process based on a cancel request from the main thread? For the purposes of my of the EXE running in the process, I can just call `Process.Close()` to exit without any side-effects, but the `Process` object is only known to the `worker_DoWork()` method, so I'll need to keep track of the `Process` instance for cancellation purposes... that's why I'm hoping there might be a better way. (if it matters, I am targeting .NET 3.5 for compatibility issues.)

Original source