Do I fail to trigger other mouse events when I press the mouse?

[fhhyyp]

The description in the gif is not accurate enough, let me redescribe it

when I hold down this control and move the mouse somewhere else,
the PointerMoved event is always fired by the same control instance.
other Pointer events cannot be triggered

If I simply move the mouse, the events for these controls will fire normally

what should I do if I want to trigger other pointer events when I hold down the mouse

public NodeJunctionView()
{
    this.PointerMoved += NodeJunctionView_PointerMoved; // this event
    this.PointerExited += NodeJunctionView_PointerExited;
    this.PointerPressed += NodeJunctionView_PointerPressed;
    this.PointerReleased += NodeJunctionView_PointerReleased;
}

private void NodeJunctionView_PointerExited(object? sender, PointerEventArgs e)
{
    Dispatcher.UIThread.InvokeAsync(InvalidateVisual, DispatcherPriority.Background);
    Debug.WriteLine($"exited source : {Guid}");
    
}

private Guid Guid = Guid.NewGuid();
private void NodeJunctionView_PointerMoved(object? sender, PointerEventArgs e)
{
    // revised the comments...
    // when I hold down this control and move the mouse somewhere else,
    // the PointerMoved event is always fired by the same control instance.
    // other instances will not be able to fire PointerMoved events

    Debug.WriteLine($"moved source : {Guid}"); 

    // other code...
}


private void NodeJunctionView_PointerReleased(object? sender, PointerReleasedEventArgs e)
{
	Dispatcher.UIThread.InvokeAsync(InvalidateVisual, DispatcherPriority.Background);
}


private void NodeJunctionView_PointerPressed(object? sender, PointerPressedEventArgs e)
{
	// other code...
}

[msneijders]

Those PointerMoved events will only go to the pressed NodeJunction because it will Capture the Pointer during Pointer Pressed.

You could undo that like so in your NodeJuntionView:

protected override void OnPointerPressed(PointerPressedEventArgs e)
{
    base.OnPointerPressed(e);
    e.Pointer.Capture(null);
}

Now when you move the pointer to another NodeJuntionView it will get the PointerMoved. But I do not know what negative side-effects this technique could have. You should check for that.

[msneijders]

Another technique, without releasing the capture, could be to make a custom event; like a ConnectingEnterEvent and a ConnectingExitEvent. And in the PointerMoved of the captured NodeJunctionView you find the underlying NodeJunctionView (find it using InputElement InputHitTest() and raise a ConnectingEnter/ExitEvent on it. That NodeJunctionView can then catch that event, and for instance set a pseudoclass like ":connecting", which you can then use to do some styling on it.

[fhhyyp]

Thank you for providing a great solution. The e.Pointer.Capture(null) does indeed bring other side effects, so I used the second method you suggested and successfully achieved the desired result.