A scenario with a requirement to display information about the entire group, including recursively all child groups, needs access to the actual items and/or subgroups. Exposing these and parent info would allow for greater flexibility in displaying custom information in group headers.

When the CollectionView is grouped and an element is removed from the source collection and inserted again immediately after that, it results in its parent group not expanding/collapsing when tapped. The tap is registered and the visual indicator of the group state is changed but the group is not actually collapsing and expanding. This issue is happening for groups with only one child item. When scrolling so the group gets our of the visible area and then scroll to the group again, the collapse/expand functionality works.

When the client picks a random item from the ItemSource and changes the value of its property for which a GroupDescriptor is set, the CollectionView crashes.

I see iOS crashes in Sentry, seems like caused by clearing the RadCollectionView bound DataSource ObservableCollection, when an item was previously selected

Maui 9.0.70
Telerik 11.0

System.NullReferenceException: Arg_NullReferenceException
  ?, in void RadCollectionViewItemView.OnIsSelectedChanged()
  ?, in static RadCollectionViewItemView()+(BindableObject b, object o, object n) => { }
  ?, in void BindableObject.OnBindablePropertySet(BindableProperty property, object original, object value, bool didChange, bool willFirePropertyChanged)
  ?, in void Element.OnBindablePropertySet(BindableProperty property, object original, object value, bool changed, bool willFirePropertyChanged)
  ?, in void BindableObject.SetValueActual(BindableProperty property, BindablePropertyContext context, object value, bool currentlyApplying, SetValueFlags attributes, SetterSpecificity specificity, bool silent)
  ?, in void BindableObject.SetValueCore(BindableProperty property, object value, SetValueFlags attributes, SetValuePrivateFlags privateAttributes, SetterSpecificity specificity)
  ?, in void BindableObject.SetValue(BindableProperty property, object value)
  ?, in void RadCollectionViewItemView.set_IsSelected(bool value)
  ?, in void RadCollectionView.SelectContainers(IEnumerable items, bool select)
  ?, in void RadCollectionView.SelectionHelperSelectionChanged(object sender, RadSelectionChangedEventArgs e)
  ?, in void <>c__DisplayClass36_0.<SelectionChangerSelectionChanged>b__0(?)+() => { }
  ?, in void ActiveSelectionScope.Dispose()
  ?, in void SelectionHelper.ClearSelection()
  ?, in void RadCollectionView.Telerik.Maui.Controls.ICollectionView.ItemsChanged(NotifyCollectionChangedEventArgs e)
  ?, in void CollectionViewModel.OnDataProviderViewChanged(object sender, ViewChangedEventArgs e)
  ?, in void DataProviderBase.RaiseViewChanged(object sender, List<AddRemoveResult> changes, NotifyCollectionChangedEventArgs args, CollectionChange action, bool affectsAggregates)
  ?, in void LocalDataSourceProvider.ProcessCollectionChanged(NotifyCollectionChangedEventArgs e)
  ?, in void LocalDataSourceProvider.DataView_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
  ?, in void EnumerableDataSourceView.RaiseCollectionChanged(object sender, NotifyCollectionChangedEventArgs args)
  ?, in void EnumerableDataSourceView.ProcessCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
  ?, in void EnumerableDataSourceView.ProcessCollectionChangedOverride(object sender, NotifyCollectionChangedEventArgs args)
  ?, in void EnumerableDataSourceView.ProcessPendingCollectionChange()
  ?, in void DataProviderBase.RaiseViewChanging(object sender, IList changedItems, CollectionChange action)
  ?, in void LocalDataSourceProvider.DataView_CollectionChanging(object sender, NotifyCollectionChangedEventArgs e)
  ?, in void EnumerableDataSourceView.HandleCollectionChangedOverride(object sender, NotifyCollectionChangedEventArgs e)
  ?, in void EnumerableDataSourceView.Telerik.Maui.IWeakEventListener.ReceiveEvent(object sender, object args)
  ?, in void WeakEventHandlerList<NotifyCollectionChangedEventArgs>.ProcessEvent(object sender, object args)
  ?, in void WeakEventHandlerList<NotifyCollectionChangedEventArgs>.OnCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
  ?, in void ObservableCollection<ViewBundle>.OnCollectionChanged(NotifyCollectionChangedEventArgs)
  ?, in void ExtObservableCollection<ViewBundle>.OnCollectionChanged(NotifyCollectionChangedEventArgs e)
  ?, in void ObservableCollection<ViewBundle>.OnCollectionReset()
  ?, in void ObservableCollection<ViewBundle>.ClearItems()
  ?, in void ExtObservableCollection<ViewBundle>.ClearItems()
  ?, in void Collection<ViewBundle>.Clear()
  ?, in void SearchViewViewModel.Dispose(bool disposing)
  ?, in void PropertyChangedNotifyingBase.Dispose()
  ?, in async void ViewBundle.Dispose(bool disposing)
  ?, in void <>c.<ThrowAsync>b__128_0(?)+(object state) => { }
  ?, in void NSAsyncSynchronizationContextDispatcher.Apply()
  ?, in void __Registrar_Callbacks__.callback_3311_Foundation_NSAsyncSynchronizationContextDispatcher_Apply(IntPtr pobj, IntPtr sel, IntPtr* exception_gchandle)

When having a CollectionView and navigating between different views when tapping on an item from the CollectionView, the item(s) look(s) selected. 

It seems the behavior is due to the mouse over and selected visual states.

Add support for sticky group headers for desktop - WinUI and MacCatalyst. 

Null Ref Exception occurs when calling ScrollItemIntoView at the time when navigating away from the page. 

When collapsing all groups, the footer still keeps bottom position and does not align with the groups. 

In RadListView, the footer is aligned to the groups when they are collapsed. Please provide such option for the CollectionView. 

Provide a built it way to notify the parent group when the items in the nested groups are changed. 

For example, there is no PropertyChanged or CollectionChanged notification that we can hook in to in order to detect updates in parent group headers when the count changes in a subgroup. Only the leaf group headers get updated, but not the parents.

 

Provide support for right-to-left flow direction: 

The current behavior is that the items

when the device language is set to an RTL language (like Hebrew or Arabic) causing the FlowDirection to be set to RightToLeft, where UI will show correctly with RTL FlowDirection, but the item's corresponding tap areas are still in the LTR positions. 

Setting the ItemViewStyle to have a Margin of any value greater than zero makes the items height to increase continuously when scrolling. 

When removing items from the collection's item source, the group header item count does not update real time. It only updates when the GroupContext is collapsed or expanded. This would also be an issue if items are added dynamically.

Our error reporting is getting multiple of these crashes:

programmatically cause a list item template to swipe itself

Steps to Reproduce

1. Create a RadCollectionView with an ObservableCollection<ButtonModel> as the ItemsSource.

2. Use a DataTemplate inside RadCollectionView.ItemTemplate to display buttons.

3. Bind button properties (IsOddClick, IsEvenClick) that should change on click.

4. Click the button inside the RadCollectionView and observe that:

5. The text updates correctly, but part of it is cut off. It seems the text does not expand 

1. Bind the CheckedItems collection of the TreeView to the CollectionView ItemsSource.

2. there aren't any items in the TreeView initially.  Add items to it

3. Start checking the checkboxes

4. The items are added to the CollectionView, still they are not visible in the control.

 

CollectionView item swipe doesn't work.

Having a RadExpander inside the ItemTemplate breaks the Drag and Drop gesture of the RadCollectionView. 

When Using MAUI CollectionView and RadExpander in the template, drag and drop works.

The content inside the swipe template is missing when using MAUI 9.0.40 and Telerik MAUI 10.0.0

Workaround:

Use MAUI 9.0.30 and Telerik MAUI 10.0.0

The RadListView Delegate sort, filter and group descriptors have bindable properties, for example: Func<object, object) KeyExtractor, Filter.
The RadCollectionView delegate descriptors use KeyLookup, Filter which type is interface and do not expose bindable properties.

the option is to implement an interface