C# Old timer overlap the new

Question

I have a small game with a timer, when a new match is started the timer must reset, but actually the new timer and the old overlap alternating. I don't understand why.

When a new game start this method it's called:

private void setGame()
{
   game = new Game();

   game.gameData.stopWatch = new StopWatch(timerLabel);
   game.gameData.scoreLabel = scoreLabel;
}

public StopWatch(Label timerLabel)
{
   this.timerLabel = timerLabel;

   _timer = new Timer();
   _timer.Interval = 1000;

   _timer.Tick += new EventHandler(_timer_Tick);
}

And then _timer_Tick it's called one time with the startData of actual match and another time with the startData of the old match. Why?

Answer 1

When you create the new instance of StopWatch , the old one timer still active.

private void setGame()
{
    if (game != null)
        game.gameData.stopWatch.StopTimer();

    game = new Game();

    game.gameData.stopWatch = new StopWatch(timerLabel);
    game.gameData.scoreLabel = scoreLabel;
}

and add StopTimer function to StopWatch class:

public StopTimer()
{
    _timer.Stop();
}

---

PS It was a quick fix, just to make the code work. Not necessarily correct from a design point of view. When System.Timers.Timer s are used, it might be better to implement Dispose pattern. See Is it necessary to dispose System.Timers.Timer if you use one in your application?

Answer 2

Make sure you only call

_timer.Tick += new EventHandler(_timer_Tick);

once.