Audio Recording issue using Windows Timer elapsed event

Question

I am recording voice from my windows application on time intervals. I made a class to start and stop the voice recording and calling its function on my form.

The class is as follows

class VoiceRecording {
    [DllImport("winmm.dll", EntryPoint = "mciSendStringA", CharSet = CharSet.Ansi, SetLastError = true, ExactSpelling = true)]
    private static extern int mciSendString(string lpstrCommand, string lpstrReturnString, int uReturnLength, int hwndCallback);
    public VoiceRecording() {

    }

    public void StartRecording() {
        mciSendString("open new Type waveaudio Alias recsound", "", 0, 0);
        mciSendString("record recsound", "", 0, 0);
    }

    public void StopRecording(int FileNameCounter) {
        mciSendString(String.Format("save recsound {0}", @"E:\WAVFiles\" + FileNameCounter + ".wav"), "", 0, 0);
        mciSendString("close recsound ", "", 0, 0);
        Computer c = new Computer();
        c.Audio.Stop();
    }
}

Now when I call these functions on button click event like

    int FileNameCounter = 1;
    private void btnStart_Click(object sender, EventArgs e) {
        VR = new VoiceRecording();
        VR.StartRecording();
    }

    private void btnStop_Click(object sender, EventArgs e) {
        VR.StopRecording(FileNameCounter++);
        VR = null;
    }

everything goes fine, no matter how slow or fast I click the buttons, the code always create numbered files.

I put the code into a loop as well like

for (int i = 0; i < 10; i++) {
   VR = new VoiceRecording();
   VR.StartRecording();
   VR.StopRecording(FileNameCounter++);
   VR = null;
}

it also runs well and creates 10 numbered files.

Till now everything is fine, and here I introduced Timer like this

System.Timers.Timer t = new System.Timers.Timer();
t.Elapsed += new ElapsedEventHandler(TimerEvent);
t.Interval = 10000;
t.Start();

private bool RecordingStarted = false;
private void TimerEvent(object sender, ElapsedEventArgs e) {
    if (RecordingStarted) {
        VR.StopRecording(FileNameCounter++);
        VR = null;
        RecordingStarted = false;
    } else {
        VR = new VoiceRecording();
        VR.StartRecording();
        RecordingStarted = true;
    }
}

Now the problem is when the code is executing inside TimerEvent, it is creating files but it is also missing some files.

For Example
Loop Creates: 1.wav, 2.wav, 3.wav, 4.wav, 5.wav, 6.wav
Timer Creates: 1.wav, 2.wav, 4.wav, 7.wav, 8.wav, 13.wav

I have debug the code, every statement is executing every time but sometimes the file is not being created.

Any help will be highly appreciated :)

Answer 1

As said by Hans Passant

System.Timers.Timer is a difficult class, creating all kinds of opportunity for undiagnosable failure. Re-entrancy is always a risk, its habit of swallowing all exceptions is especially troublesome. Just don't use it, you don't need it. Use a regular Winforms timer instead.

Using Winforms timer solved the problem. Now the numbered files are being created as I wanted them to be. :)

Thank You Hans Passant