Hello
In my project I use the TreeViewAdv
control to switch between different projects items which can be edited by the
user but before switching I need to validate the input and if a validation
error occurs I need to prevent the switch.
As there is no event in TreeViewAdv
which allows me to cancel the selection of a new item I instead try to revert
the selection back to it's previous state.
In my OnSelectedItemChanged
code I try:
myTree.SelectedItems.Clear();
myTree.SelectedTreeItem = oldSelItem;
which causes another
SelectedItemChanged event as expected, but after I ignore this and set
e.Handled = true I receive another SelectedItemChanged
event which has an SelectedItems.Count of 2 and SelectedItems[0] is the
oldSelItem and SelectedItems[1] contains the item the user selected previously
Again I have to clear the SelectItems and set it to oldSelItem to
finally have my old selection back but this behaviour is very strange and
complicate to prevent a selection change.
Here the sequence of the
events:
TreeViewAdv
with current selected item id: 3070
User clicks on
item with id 3153 and causes SelectedItemChanged event with item id 3153
Validation of
current item (3070) fails and needs to prevent the selection change:
myTree.SelectedItems.Clear();
myTree.SelectedTreeItem = oldSelItem;
SelectedItemChanged
event with item id 3070 (as expected)
e.Handled = true;
return;
SelectedItemChanged
event with item id 3070 and 3153 (unexpected)
here I need
myTree.SelectedItems.Clear();
myTree.SelectedTreeItem = oldSelItem;
again
SelectedItemChanged
event with item id 3070 (as expected) to finally change back to the old item.
Is there a better way to handle this and what causes this strange SelectedItemChanged event?
Regards,
Reinhard
