How to make TreeView trigger selection on mouse released instead to pointer pressed

[dabblob]

Hi,
I’m implementing a custom drag & drop handler for a custom data view based on TreeView / TreeViewItem, relying directly on pointer events (PointerPressed, PointerMoved, PointerReleased) rather than the built-in drag/drop APIs.

While this mostly works, I’m running into a conflict between TreeView selection logic and drag initiation, and I’m looking for guidance on the intended pattern here or whether this is an area that could benefit from a small behavior change.

Problem Summary :
Currently, TreeViewItem selection happens on PointerPressed. This causes several issues when implementing drag & drop:

Selection clears before drag intent is known : On PointerPressed, TreeView selection logic runs immediately.
If the user intends to drag, selection is already modified/cleared before I can decide whether this is a click or a drag.
I can cache the selected items before selection changes, so the drop logic works, but Visual state becomes incorrect
Selection visuals change immediately on press.
When a drag starts, the UI appears to “lose” selection briefly, which looks like a bug to users.
Range / multi-selection becomes sluggish

Because selection and drag logic are effectively “fighting” each other on pointer events, range selection feels slow.
In PointerPressed, I Detect the pressed item ,Cache the selected items before selection is cleared .
Start drag once the pointer movement exceeds a threshold
This keeps drag/drop behavior functionally correct, but the selection visuals and UX suffer, which feels fundamentally wrong.

Suspected Better Model
Ideally, selection would:
Be committed on PointerReleased
This would allow:
Clean separation between click and drag
without having to rewrite the selection behaviors

I found this PR which seems very relevant: #20356
However, I’m not fully sure: Whether this PR already solves this scenario
Whether it introduces a recommended pattern I should adopt

thank you .

[JazSquared]

I think we are working on similar logic. My solution is to just set e.handled = true; in OnPointerPressed and handle selection manually in OnPointerReleased:

private void OnPointerPressed(object? sender, PointerPressedEventArgs e)
	{
		if (!IsOnDragHandle(e.Source as Visual)) return;

		_dragStartPoint = e.GetPosition(AssociatedObject);
		e.Handled = true;
	}

	private async void OnPointerMoved(object? sender, PointerEventArgs e)
	{
		if (_dragStartPoint is null) 
			return;

		if (!e.GetCurrentPoint(AssociatedObject).Properties.IsLeftButtonPressed)
		{
			_dragStartPoint = null;
			return;
		}

		var currentPos = e.GetPosition(AssociatedObject);
		var dx = Math.Abs(currentPos.X - _dragStartPoint.Value.X);
		var dy = Math.Abs(currentPos.Y - _dragStartPoint.Value.Y);
		
		if (dx < _dragThreshold && dy < _dragThreshold) 
			return;

		_dragStartPoint = null;

		await StartDrag(e);
	}

	private void OnPointerReleased(object? sender, PointerReleasedEventArgs e)
	{
		// If we never left the dead zone, it was a click —> select the item
		if (_dragStartPoint is not null)
		{
			var item = GetTreeViewItem(e.Source as Visual);

			if (item?.DataContext is not null && AssociatedObject is TreeView tv)
			{
				if (e.KeyModifiers.HasFlag(KeyModifiers.Control) || e.KeyModifiers.HasFlag(KeyModifiers.Shift))
				{
					if (tv.SelectedItems!.Contains(item.DataContext))
						tv.SelectedItems.Remove(item.DataContext);
					else
						tv.SelectedItems!.Add(item.DataContext);
				}
				else
				{
					tv.SelectedItems!.Clear();
					tv.SelectedItems.Add(item.DataContext);
				}
			}
		}

		_dragStartPoint = null;
	}