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Author Topic: DragDrop ghost image with DragObject; fine, but SIGSEV at Drop - why?  (Read 2682 times)

d7_2_laz

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Re: DragDrop ghost image with DragObject; fine, but SIGSEV at Drop - why?
« Reply #15 on: April 23, 2021, 05:04:22 pm »
Hello dseligo and GetMem, thanks a lot for your attention and replies. I appreciate them a lot!

Yes, i suspected such as mentioned in the OP  where i found it to halt in TDragImageListResolution.HideDragImage
Because the memory of "Dragging" (resp. FDragging) could not be accessed.
I thought about myself to work around querying "if Assigned(Self)" or simlar higher in the hierarchy  for to get rid of the exception.
The reason why i did it not , was that i felt that the real source of the issue would be simply covered, not solved.
Maybe an object has been freed too early for some reasons (too early at least from the perspective of the use case). But why??? At the moment of the drop ...

But the operation is so basic that i was in doubt: "that cannot be, i must have done something wrong".  .... But in fact i could not find it.
I had been wondering how others do that: treeview with icons, use the icons as drag image .... It's a so basic and trivial task l ...

--
I just tried to post this reply and to ask, whether the change might be part of the source (some more queries for to be safe that the object does exist). when seeing the update that you (GetMem) did apply the changes to the source.
That's fantastic!!  :) :) :) :) :)  Thank you!


Lazarus 3.2  FPC 3.2.2 Win10 64bit

dseligo

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Re: DragDrop ghost image with DragObject; fine, but SIGSEV at Drop - why?
« Reply #16 on: April 23, 2021, 07:38:52 pm »
I applied the changes in r. 65055.

Revision number will soon be 65535. I hope that counter variable is more than 16 bits. :D

balazsszekely

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Re: DragDrop ghost image with DragObject; fine, but SIGSEV at Drop - why?
« Reply #17 on: April 23, 2021, 08:18:01 pm »
@dseligo
Quote
Revision number will soon be 65535. I hope that counter variable is more than 16 bits.
You have a digital mind. I will send you a beer after 65535.  ;)

dseligo

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Re: DragDrop ghost image with DragObject; fine, but SIGSEV at Drop - why?
« Reply #18 on: April 23, 2021, 10:54:38 pm »
@dseligo
Quote
Revision number will soon be 65535. I hope that counter variable is more than 16 bits.
You have a digital mind. I will send you a beer after 65535.  ;)

8)

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