<![CDATA[Item gets duplicated in the model after drag-n-drop in QTreeView]]>I have a QStandardItemModel() with a number of QStandardItem() elements displayed in a customized QTreeView().
It's a simple tree, and after the element is dragged and dropped I need to save this change to the database.
The drag-n-drop mode set to QAbstractItemView.InternalMove
Now here's the problem that I'm facing.
Suppose we had a tree:

parent
- childA
- childB
- childC

And dragged childC above childB:

parent
- childA
- childC
- childB

I'm listing the items using this code:

self.model.itemChanged.connect(self.item_changed)

...

def item_changed(self, item):
    par = item.parent()
        for i in range(0,par.rowCount()):
            print(i,par.child(i).text())

And it returns this:

childA
childC
childB
childC

I.e. it lists the dragged element twice - at its previous position and at its current position. In the tree everything is fine, the items are not duplicated.

Why is that? How can I reliably track the reorder operations like this to save this state?
Thanks.

P.S. I also saw the same problem when I tried to get the data from the model inside dropEvent() of my QTreeView() implementation.

]]>https://forum.qt.io/topic/124455/item-gets-duplicated-in-the-model-after-drag-n-drop-in-qtreeviewRSS for NodeSun, 14 Jun 2026 09:45:21 GMTFri, 05 Mar 2021 17:56:55 GMT60<![CDATA[Reply to Item gets duplicated in the model after drag-n-drop in QTreeView on Fri, 05 Mar 2021 18:57:47 GMT]]>Looks like this is the expected behavior, and it's described here: https://stackoverflow.com/questions/52873025/pyqt5-qlistview-drag-and-drop-creates-new-hidden-items

When an item moves from position i to position j, what is done is:

  • Insert an item in position j
  • Copy the data to the new item, at this moment the itemChanged signal is emitted and therefore you see that there are elements of more
  • Delete the item that was in the position i.

So my question is: which method should I use to save the data after the item in the position i was deleted?

At the moment it looks like I have to save the data in one of the 2 places:

  • in dropEvent() of my TreeView
  • in a method called by itemChanged() of the model, where I'll have to compare the model indexes to distinguish between the new and the old position of the element
]]>https://forum.qt.io/post/647911https://forum.qt.io/post/647911Fri, 05 Mar 2021 18:57:47 GMT