toToggleOnDblClick and remove node in OnNodedblClick event

[Dzyszla]

I have some custom code in OnNodeDblClick. There is some modal window, and next remove items from tree.

Then sometimes got access violation in method TBaseVirtualTree.AdjustTotalHeight on line:

      if not (vsVisible in Run.States) or (Run = FRoot) or
        (Run.Parent = nil) or not (vsExpanded in Run.Parent.States) then

Callstack:

Maybe event procedure for OnNOdeDblClick should return some parameter like handled and if true, then stop trying execute other code base on doubleclick?

[joachimmarder]

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Maybe event procedure for OnNOdeDblClick should return some parameter like handled and if true

This would be a breaking change to the event signature, which is generally not a good idea.

[Dzyszla]

Here is example. In this case after node deleted, I myself write some trash on old memory space. In huge project with more memory operations it's not nesesery.

VST.zip

Try to dblclick on item several times (mayby one)

The problem is executing code after my event procedure, where I remove hit item, and VST still this is exists. There are no way to tell: "hey, don't do anything else, i done it myself / i removed this item".

I know it's braking change. But is another way to remove item in doubleclick event procedure (sometimes) with enabled toToggleOnDblClick option?

[joachimmarder]

The best I can do is to check if (vsDeleting in HitNode.States) immediately after executing the event handler, however if the memory was meanwhile overwritten, that won't help.

Please remove the flag MiscOptions.toToggleOnDblLick which prevents the code that ran into AVs to be executed. This solved the problem in the sample project. You can toggle the node manually in your own code.

BTW, I think the FillMemory() covers too many bytes, the user data is much smaller than 80 Bytes.

[Dzyszla]

The best I can do is to check if (vsDeleting in HitNode.States) immediately after executing the event handler, however if the memory was meanwhile overwritten, that won't help.

But after delete in event, node not exist. So event procedure will be last of all internal or, how I wrote, return handled flag to prevent execute internal functions (best).

Other solution to resign from using pointers and make node as interfaced object. But then adding and removing nodes will be slower :(

Please remove the flag MiscOptions.toToggleOnDblLick which prevents the code that ran into AVs to be executed. This solved the problem in the sample project. You can toggle the node manually in your own code.

Yes, in this case helps. But this is not only one function can execute on duble click after event procedure faired.

BTW, I think the FillMemory() covers too many bytes, the user data is much smaller than 80 Bytes.

PVirtualNode allocate 80 bytes + node data size.