How can I maintain a C# process open?

Question

I wrote this:

class Script
{
    [STAThread]
    static public void Main(string[] args)
    {
        SpeechRecognitionEngine _recognizer = new SpeechRecognitionEngine();
        // I do many thinks with this _recognizer
    }
}

My applications starts and stops immediately. What should I do to so that my application remains open and responsive to my _recognizer ? I don't want to write a Windows form or console application. I would like to keep my voice recognizer as background application.

Answer 1

Is this a Console Application, I do suppose..

Console.Readline();

will wait user to type enter, and then exit.

---

UPDATE

Look at this thread Developing a simple Windows system tray desktop app to consume a .NET web service. Maybe this is similar to your needs.

Answer 2

When the main-method returns, the application gets closed, yes. In that event, all background-threads are aborted. What remains are foreground-threads. They keep the process alive. That's what the Message Loop does.

So, you must have any kind of loop in a foreground-thread (either in the main-method or any newly created thread with the IsBackground-property set to false).

That could look like:

SpeechRecognitionEngine _recognizer = new SpeechRecognitionEngine();
while (_recognizer.IsActive) // or something similar
{
    Thread.Sleep(100);
}

That is fairly not a beauty, since it wastes resources and makes usage of Thread.Sleep. When SpeechRecognitionEngine has an event when it likes to quit, you could have something like:

ManualResetEvent reset = new ManualResetEvent(false);
SpeechRecognitionEngine _recognizer = new SpeechRecognitionEngine();
_recognizer.Quitting += new EventHandler((sender, args) =>
{
    reset.Set();
});
reset.WaitOne();

The ManualResetEvent allows you to wait for the Quitting-event. After Set was called, WaitOne returns and your application/process ends.

Answer 3

You should write

class Script
{
    [STAThread]
    static public void Main(string[] args)
    {
        _completed = new ManualResetEvent(false);
        SpeechRecognitionEngine _recognizer = new SpeechRecognitionEngine();
        // I do many thinks with this _recognizer
        // Add an exit event that should call _completed.Set();
        _completed.WaitOne();
    }
}

implementation and tutorial found here

static void Main(string[] args)
{
    _completed = new ManualResetEvent(false);
    SpeechRecognitionEngine _recognizer = new SpeechRecognitionEngine();
    _recognizer.LoadGrammar(new Grammar(new GrammarBuilder("test")) Name = { "testGrammar" }); // load a grammar
    _recognizer.LoadGrammar(new Grammar(new GrammarBuilder("exit")) Name = { "exitGrammar" }); // load a "exit" grammar
    _recognizer.SpeechRecognized += _recognizer_SpeechRecognized;
    _recognizer.SetInputToDefaultAudioDevice(); // set the input of the speech recognizer to the default audio device
    _recognizer.RecognizeAsync(RecognizeMode.Multiple); // recognize speech asynchronous
    _completed.WaitOne(); // wait until speech recognition is completed
    _recognizer.Dispose(); // dispose the speech recognition engine
}

void _recognizer_SpeechRecognized(object sender, SpeechRecognizedEventArgs e)
{
     if (e.Result.Text == "test") // e.Result.Text contains the recognized text
     {
         Console.WriteLine("The test was successful!");
     } 
     else if (e.Result.Text == "exit")
     {
         _completed.Set();
     }
}

Answer 4

Maybe You want a Windows Service to run? You can check out it here.

In the

protected override void OnStart(string[] args)
{ 
    eventLog1.WriteEntry("my service started"); 
}

part of the tutorial You can insert the SpeechRecognitionEngine _recognizer = new SpeechRecognitionEngine(); code inside. I assume that will listen to some events. You set the callbacks for those events also here.

When You fully close the application You take care of the _recognizer here:

protected override void OnStop()
{ 
    eventLog1.WriteEntry("my service stoped");
}