DispatcherTimer apply interval and execute immediately

Question

Basically when we apply some interval ie 5 sec we have to wait for it.

Is it possible to apply interval and execute timer immediately and don't wait 5 sec? (I mean the interval time).

Any clue?

Thanks!!

public partial class MainWindow : Window
    {
        DispatcherTimer timer = new DispatcherTimer();

        public MainWindow()
        {
            InitializeComponent();

            timer.Tick += new EventHandler(timer_Tick);
            this.Loaded += new RoutedEventHandler(MainWindow_Loaded);
        }

        void timer_Tick(object sender, EventArgs e)
        {
            MessageBox.Show("!!!");
        }

        void MainWindow_Loaded(object sender, RoutedEventArgs e)
        {
            timer.Interval = new TimeSpan(0, 0, 5);
            timer.Start();
        }
    }

If you want something to occur immediately, why not just execute it immediately? — dlev, Jul 03 '12 at 17:58
I don't see what's inelegant about calling a method directly. You should probably create a new method, which is called in both places, but the idea is the same: if you want something to occur now, then just do it! — dlev, Jul 03 '12 at 18:07
@dlev Initially I did as you suggesting but now I like the Austin Salonen solution. Thanks anyway! — NoWar, Jul 03 '12 at 18:15

score 21 · Answer 1 · answered Jul 03 '12 at 17:59

21

There are definitely more elegant solutions, but a hacky way is to just call the timer_Tick method after you set the interval initially. That'd be better than setting the interval on every tick.

answered Jul 03 '12 at 17:59

Jin

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Why is it better than setting the interval on every tick? Please elaborate. – Manuzor Sep 19 '19 at 08:25

score 11 · Accepted Answer · edited Jun 15 '15 at 10:59

11

Initially set the interval to zero and then raise it on a subsequent call.

void timer_Tick(object sender, EventArgs e)
{
    ((Timer)sender).Interval = new TimeSpan(0, 0, 5);
    MessageBox.Show("!!!");
}

edited Jun 15 '15 at 10:59

Ignatius

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answered Jul 03 '12 at 17:58

Austin Salonen

49,173
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Jin's solution is cleaner. – Cœur Jul 22 '14 at 15:27

score 6 · Answer 3 · answered Oct 17 '14 at 10:22

could try this:

timer.Tick += Timer_Tick;
timer.Interval = 0;
timer.Start();

//...

public void Timer_Tick(object sender, EventArgs e)
{
  if (timer.Interval == 0) {
    timer.Stop();
    timer.Interval = SOME_INTERVAL;
    timer.Start();
    return;
  }

  //your timer action code here
}

Another way could be to use two event handlers (to avoid checking an "if" at every tick):

timer.Tick += Timer_TickInit;
timer.Interval = 0;
timer.Start();

//...

public void Timer_TickInit(object sender, EventArgs e)
{
    timer.Stop();
    timer.Interval = SOME_INTERVAL;
    timer.Tick += Timer_Tick();
    timer.Start();
}

public void Timer_Tick(object sender, EventArgs e)
{
  //your timer action code here
}

However the cleaner way is what was already suggested:

timer.Tick += Timer_Tick;
timer.Interval = SOME_INTERVAL;
SomeAction();
timer.Start();

//...

public void Timer_Tick(object sender, EventArgs e)
{
  SomeAction();
}

public void SomeAction(){
  //...
}

score 1 · Answer 4 · answered Mar 09 '20 at 17:27

That's how I solved it:

dispatcherTimer = new DispatcherTimer();
dispatcherTimer.Tick += new EventHandler(DispatcherTimer_Tick);
dispatcherTimer.Interval = new TimeSpan(0, 0, 10);
dispatcherTimer.Start();

DispatcherTimer_Tick(dispatcherTimer, new EventArgs());

Works for me without any issues.

Hakan Fıstık · Answer 5 · 2022-12-19T10:24:28.633

Disclaimer: This answer is not for the OP because he wants to use DispatcherTimer
But if you do not have this limitation and you can use another Timer, then there is a cleaner solution

You can use System.Threading.Timer

The most important thing is setting dueTime:0

System.Threading.Timer timer = new Timer(Callback, null, dueTime:0, period:10000);

The documentation of the dueTime is the following

The amount of time to delay before callback is invoked, in milliseconds. Specify Infinite to prevent the timer from starting. Specify zero (0) to start the timer immediately.

and your callback is like this

private void Callback(object? state) =>
{
}

Again this does not use DispatcherTimer but it could solve your problem

DispatcherTimer apply interval and execute immediately

5 Answers5