Fix SelectionChanged not raised on collection Reset#20942
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NathanDrake2406 wants to merge 1 commit intoAvaloniaUI:masterfrom
Open
Fix SelectionChanged not raised on collection Reset#20942NathanDrake2406 wants to merge 1 commit intoAvaloniaUI:masterfrom
NathanDrake2406 wants to merge 1 commit intoAvaloniaUI:masterfrom
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…deselected When a collection bound to a SelectingItemsControl (e.g. ListBox) was cleared via NotifyCollectionChangedAction.Reset, the SelectionChanged event was not raised despite the selection being lost. The root cause was in InternalSelectionModel.OnSourceReset: the base SelectionModel.OnSourceReset() directly reset _selectedIndex to -1 before any Operation could capture the old selection state. The subsequent SyncFromSelectedItems created an Operation that saw no change (old and new both -1), so CommitOperation never fired SelectionChanged. The fix snapshots _writableSelectedItems before sync, diffs against the post-sync state to find items that were actually lost (not merely re-selected at a new index after reorder), and injects them as DeselectedItems on the pending Operation — following the same pattern used by OnSelectionRemoved for individual item removals. Fixes AvaloniaUI#20897
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You can test this PR using the following package version. |
MrJul
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backport-candidate-11.3.x
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Summary
SelectionChangedevent is now raised when a bound collection is cleared (or reset) and the control had a selectionInternalSelectionModel.OnSourceResetcalledSyncFromSelectedItems()which created anOperationafterSelectionModel.OnSourceReset()had already reset_selectedIndexto-1— the Operation saw no change and never firedSelectionChanged_writableSelectedItemsbefore sync, diff against post-sync state to find actually-lost items, inject asDeselectedItemson the pending Operation (same pattern asOnSelectionRemoved)Test plan
SelectionChangedwith deselected item inRemovedItemsSelectionChangedwith all deselected itemsFixes #20897