Re: 0xFEEEFEEE
I'm assuming that where you delete the item you don't have access to the
tree control.
The way I normally handle something like this is when an object that is
referenced in multiple places is getting deleted, I put the pointer in a
DeletedItemsList (this can be a list, vector, CList, CArray....) and I
signal that UI objects that they need to refresh themselves. At that point
they would first check their items against the DeleteItemsList and if there
is a match they would delete their UI item (tree item, list item....) before
refreshing anything else. And then clear the deleted list.
AliR.
"GT" <ContactGT_removeme_@hotmail.com> wrote in message
news:0015424d$0$2882$c3e8da3@news.astraweb.com...
I have a CTreeCtrl derived class. When I populate the tree, I create (new)
an object and point the treeitem's LParam at the new object. The object
that I create is basically a struct and holds some numerical information
and a pointer to another object - a 'Worker' object.
At some point in time, the Worker object is deleted from the system. This
is expected and normal behaviour. At some point in time following the
Worker delete, the appropriate redraw method is automatically triggered
and I then cycle round my tree and check that all nodes are in the correct
place. When I reach the nodes that have LParams pointing to an object that
points to a deleted Worker, I have a problem. When I retreive my tree's
pointer to the deleted Worker, it is not a NULL pointer, but points to
what appears to be a valid object (memory location looks normal). I know
that (in debug mode) this memory location is not valid, but if I try to do
anything to what appears to be a normal object, then I get a crash -
accessing 0xfeeefeee error - accessing a memory location that has been
erased.
I understand why I am seeing this crash - I am using an area of memory
that has gone! But I need help with the code required to test for this
situation!
Just to recap - My CTreeCtrl items hold a pointer to an object, which in
turn holds a pointer to a Worker object that has been deleted. That Worker
pointer looks OK (valid memory address), so testing against NULL is
useless, but when I try to do anything to the object it I get a crash (due
to it being deleted). How do I test for this?
I have tried calling an operation on the Worker object inside a try-catch
loop, so that I can deal with the problem in the catch area, but it still
just crashes before hitting the catch(...) line.
Thanks,
GT