CODEWITHSUNDEEP
c#timerstopwatch
user1678541
user1678541

Reputation:

Can I use a timer to update a label every x milliseconds

This is my code:

Stopwatch timer = new Stopwatch();
timer.Start();
while (timer.ElapsedMilliseconds < 3000) {
    label1.Text = Convert.ToString( timer.ElapsedMilliseconds );
}
timer.Stop();

My intetion was to update the label's text in real time, so if timer.ElapsedMilliseconds == 1350, then label1.Text = 1350. How can I do this? Thanks in advance!

Upvotes: 3

Views: 18799

Answers (4)

Adrian Thompson Phillips
Adrian Thompson Phillips

Reputation: 7151

If you want it update every second you could use the modulus operator in your while loop:

Stopwatch timer = new Stopwatch();

timer.Start();

while (timer.ElapsedMilliseconds < 3000) {
    if (timer.ElapsedMilliseconds % 1000 == 0)
    {
        label1.Text = timer.ElapsedMilliseconds.ToString();
    }
}

timer.Stop();

The modulus operator gives the remainder of a division operation, if the milliseconds are a multiple of 1,000 it will return 0.

I'd probably look into using Timers. You do a lot of spinning using the above technique, that may cause your UI to be unresponsive.

Upvotes: 1

Tigran
Tigran

Reputation: 62256

You better to use System.Windows.Forms.Timer for this, and not Stopwatch()

Even if that timer is less accurate then StopWatch(..) it gives you a good control.

Just example sniplet:

   myTimer.Tick += new EventHandler(TimerEventProcessor);       
   myTimer.Interval = 1350;
   myTimer.Start();

   private void TimerEventProcessor(...){          
     label1.Text = "...";
   }

Upvotes: 9

Marc Gravell
Marc Gravell

Reputation: 1062925

You cannot update the UI in a tight loop like that, because while the UI thread is running that code, it isn't responding to paint events. You can do nasty things like "DoEvents()", but please don't... it would be better to just have a Timer and update the UI periodically when the timer event fires; every 50ms would be the absolute fastest I'd go, personally.

Upvotes: 5

&#216;yvind Br&#229;then
&#216;yvind Br&#229;then

Reputation: 60694

Is this a WinForms app?

The problem is that while your loop runs, it does not give any other tasks (like updating the GUI) any possibility to get done, so the GUI will update the the entire loop is complete.

You can add a quick and "dirty" solution here (if WinForms). Modify your loop like this:

while (timer.ElapsedMilliseconds < 3000) {
  label1.Text = Convert.ToString( timer.ElapsedMilliseconds );
  Application.DoEvents();
}

Now the label should update in between the loop runs.

Upvotes: 1

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