How to Implement "SizeChanged"

[timunie]

Discussed in #8473

^{Originally posted by yaoyulian July 9, 2022}
In WPF: <>UserControl SizeChanged="UserControl_SizeChanged"
Avalonia do not have "SizeChanged". I tryed "LayoutUpdated", But it made UI halted. Please Add "SizeChanged".

@robloo

[sakya]

You can observe the bounds property

  _canvas = this.FindControl<Canvas>("Canvas");
  var bounds = _canvas.GetObservable(Canvas.BoundsProperty);
  bounds.Subscribe(value =>
  {
      ...
  });

[robloo]

@sakya Yes, I know. SizeChanged has some advantages:

1. For better compatibility with WPF
2. Doesn't require ReactiveUI methodology
3. It actually has more features
4. It only checks for size (not position) changes