MouseUp, DropObject firing order

General
1

Hi
I’ve found an intermittent problem with my app. During drag and drop I find that MouseUp usually fires before DropObject, but occasionally, like one in 10 events, they fire around the other way. Of course that tends to mess things up a bit when one is dependent upon the results of the other.

Does anyone have any experience of this?

Jim

2

The only comment I have is that over the 14 years I have been using RB/RS/Xojo, I have repeatedly been advised not to depend on the order of event firings.

3

Yip, that sounds like a sensible solution. Enter Timer stage-left.

Trouble is I now have so many timers running to catch the right event order, that I’m not sure which order the timers are running in…

4

[quote=151507:@James Pitchford]Hi
I’ve found an intermittent problem with my app. During drag and drop I find that MouseUp usually fires before DropObject, but occasionally, like one in 10 events, they fire around the other way. Of course that tends to mess things up a bit when one is dependent upon the results of the other.

Does anyone have any experience of this?
[/quote]

Since the dropObject cannot take place without MouseUp having taken place, why not put all your code in there ?

5

The drop might not take place. You can have MouseUp without DropObject.

6

Yes, if the mouseUp takes place outside of the drop area. But that can be detected.

7

Or if they hit Escape to cancel the drag. Or…

8

This was precisely the problem - sometimes the dropObject would fire before the MouseUp - cannot explain why.
In the end I added a Timer to go off 10msec after the dropObject to ensure both events had taken place before doing the work. Seems to work fine at the moment.

Jim

9

There’s no requirement for a timer in this situation. Add a boolean property to the window named “bothDragEventsHappened”. In both the MouseUp and DropObject handlers, use this code:

if bothDragEventsHappened then
ProcessTheDragEvent //a window method that processes the drag
bothDragEventsHappened=false
else
bothDragEventsHappened=true
end

10

What happens when both events don’t fire and the flag doesn’t get reset?