Merge pull request #367 from BAndysc/layout_cycle

Fix layout cycle error in ProportionalStackPanel

src/Avalonia.Controls.ProportionalStackPanel/ProportionalStackPanel.cs

@@ -3,6 +3,7 @@
 using System.Linq;
 using Avalonia.Data;
 using Avalonia.Layout;
+using Avalonia.VisualTree;
 
 namespace Avalonia.Controls;
 
@@ -11,6 +12,8 @@ namespace Avalonia.Controls;
 /// </summary>
 public class ProportionalStackPanel : Panel
 {
+ private bool isAssigningProportions;
+
  /// <summary>
  /// Defines the <see cref="Orientation"/> property.
  /// </summary>
@@ -80,7 +83,20 @@ public static void SetIsCollapsed(AvaloniaObject control, bool value)
  control.SetValue(IsCollapsedProperty, value);
  }
 
- private void AssignProportions(global::Avalonia.Controls.Controls children)
+ private void AssignProportions()
+ {
+ isAssigningProportions = true;
+ try
+ {
+ AssignProportionsInternal(Children);
+ }
+ finally
+ {
+ isAssigningProportions = false;
+ }
+ }
+
+ private static void AssignProportionsInternal(global::Avalonia.Controls.Controls children)
  {
  var assignedProportion = 0.0;
  var unassignedProportions = 0;
@@ -221,7 +237,7 @@ protected override Size MeasureOverride(Size constraint)
  var maximumHeight = 0.0;
  var splitterThickness = GetTotalSplitterThickness(Children);
 
- AssignProportions(Children);
+ AssignProportions();
 
  var needsNextSplitter = false;
  double sumOfFractions = 0;
@@ -344,7 +360,7 @@ protected override Size ArrangeOverride(Size arrangeSize)
  var splitterThickness = GetTotalSplitterThickness(Children);
  var index = 0;
 
- AssignProportions(Children);
+ AssignProportions();
 
  var needsNextSplitter = false;
  double sumOfFractions = 0;
@@ -492,7 +508,17 @@ static ProportionalStackPanel()
  {
  AffectsParentMeasure<ProportionalStackPanel>(IsCollapsedProperty);
  AffectsParentArrange<ProportionalStackPanel>(IsCollapsedProperty);
- AffectsParentMeasure<ProportionalStackPanel>(ProportionProperty);
- AffectsParentArrange<ProportionalStackPanel>(ProportionProperty);
+
+ ProportionProperty.Changed.AddClassHandler<Control>((sender, e) =>
+ {
+ if (sender.GetVisualParent() is not ProportionalStackPanel parent)
+ return;
+
+ if (parent.isAssigningProportions)
+ return;
+
+ parent.InvalidateMeasure();
+ parent.InvalidateArrange();
+ });
  }
 }