Async process start and wait for it to finish

Question

I am new to the thread model in .net. What would you use to:

1. start a process that handles a file (process.StartInfo.FileName = fileName;)
2. wait for th

Answer 1

Adding an advanced alternative to this old question. If you want to wait for a process to exit without blocking any thread and still support timeouts, try the following:

    public static Task WaitForExitAsync(this Process process, TimeSpan timeout)
    {
        ManualResetEvent processWaitObject = new ManualResetEvent(false);
        processWaitObject.SafeWaitHandle = new SafeWaitHandle(process.Handle, false);

        TaskCompletionSource tcs = new TaskCompletionSource();

        RegisteredWaitHandle registeredProcessWaitHandle = null;
        registeredProcessWaitHandle = ThreadPool.RegisterWaitForSingleObject(
            processWaitObject,
            delegate(object state, bool timedOut)
            {
                if (!timedOut)
                {
                    registeredProcessWaitHandle.Unregister(null);
                }

                processWaitObject.Dispose();
                tcs.SetResult(!timedOut);
            },
            null /* state */,
            timeout,
            true /* executeOnlyOnce */);

        return tcs.Task;
    }

Again, the advantage to this approach compared to the accepted answer is that you're not blocking any threads, which reduces the overhead of your app.