UWP: Map control ZoomFinished event

Question

I need to execute some code when the user finishes to zoom in/out the map. Its ZoomLevelChanged event is raised as the user zooms in or out, so it is not a solution for me (mainly because the code i want to execute is a pretty expensive operation). Any ideas?

Maybe set a timer when the user *starts* zooming, and if the event is called again, reset the timer. After the timer reaches say, 3 seconds, you can assume that they have finished zooming. — Mike Eason, Aug 25 '16 at 07:10
@MikeEason not the cleanes way i can think of but, i think it might work — Alex, Aug 26 '16 at 07:32

score 2 · Accepted Answer · answered Aug 26 '16 at 07:39

If the performance is the main issue here, you can "rerender" your map elements only when the zoom level changes from one integer to another (1->2, 2->3 and so on) (skiping the part after coma). As far as I know the maximum value for ZoomLevel is 20 (for 2D) mode. So I think it must be smooth enough for the user not to notice.

Some code:

public int ZoomLevel {get; set;} = initialZoomLevel;

private void OnZoomLevelChanged(object sender, EventArgs args)
{
    if((int)Map.ZoomLevel!=ZoomLevel)
    {
        //Rerender stuff
    }
}

I actualy already did this. and you are right. It is smooth enough for user not to notice — Alex, Aug 26 '16 at 07:40

score 0 · Answer 2 · answered Sep 08 '16 at 06:27

I believe a better solution is to listen to the LoadingStatusChanged event, then take action when you get back MapLoadingStatus.Loaded.

public void LoadingStatusChangedEventHandler(MapControl sender, Object o)
{
    if (sender.LoadingStatus == MapLoadingStatus.Loaded)
    {
        // The map has stopped moving and finished rendering
        // If necessary, check that zoom level is different
        DoExpensiveOperation();
    }
}

I know the documentation for that event isn't great, but there's a little more information at this code sample, and you may be able to find even more on the git repo.

Good luck!!

UWP: Map control ZoomFinished event

2 Answers2