Fixing out of range exception on tree view (#3574)

Keboo · web-flow · commit 3aa4967d33ee · 2024-05-27T01:33:03.000Z
This occurs when IsExpanded is set on a virtualized container that has been removed. Fixes #3572
diff --git a/src/MaterialDesignThemes.Wpf/TreeListView.cs b/src/MaterialDesignThemes.Wpf/TreeListView.cs
@@ -84,6 +84,8 @@ internal void ItemExpandedChanged(TreeListViewItem item)
         if (InternalItemsSource is { } itemsSource)
         {
             int index = ItemContainerGenerator.IndexFromContainer(item);
+            //Issue 3572
+            if (index < 0) return;
             var children = item.GetChildren().ToList();
             bool isExpanded = item.IsExpanded;
             itemsSource.SetIsExpanded(index, isExpanded);

Original file line number	Diff line number	Diff line change
`@@ -84,6 +84,8 @@ internal void ItemExpandedChanged(TreeListViewItem item)`
`84`	`84`	`if (InternalItemsSource is { } itemsSource)`
`85`	`85`	`{`
`86`	`86`	`int index = ItemContainerGenerator.IndexFromContainer(item);`
	`87`	`+ //Issue 3572`
	`88`	`+ if (index < 0) return;`
`87`	`89`	`var children = item.GetChildren().ToList();`
`88`	`90`	`bool isExpanded = item.IsExpanded;`
`89`	`91`	`itemsSource.SetIsExpanded(index, isExpanded);`