Follow this tutorial https://docs.telerik.com/devtools/xamarin/controls/listview/listview-features-load-on-demand#loading-mode-with-collection 

It works on Android and iOS, but on UWP it is defaulting to Explicit mode and clicking the load button crashes the app.

The staggered layout lays out items in a staggered grid formation. the layout is available as follow:

Telerik Ui for Xamarin.iOS ListView

Telerik UI for Xamarin.Android ListView

Telerik UI for UWP ListView

Hello,

I receive often a NullReferenceException in ListViewGroupHeader ArrangeOverride method.

The error happens only in UWP.

Unfortunately, I cannot create a project to reproduce the error.

Best regards,

When RadListView is in grid mode (SpanCount > 0), there is no spatial navigation with the keyboard.

Up and down arrows move the focused item, left and right arrows don't. (Also: it doesn't seem to be possible to style the focused item…)

Crude drawing:

Only the first column has keyboard navigation, up and down. It's invisible, though; internally, an item is focused and will execute ItemTap when pressing the return key, or will select the item when pressing the spacebar. That part is fine.

After clicking/tapping an item in any column after the first one and then pressing the down arrow, for example, we get this:

Pink is where we clicked/tapped, cyan is what's internally focused after pressing the down arrow. 

Please note again that focus != selection. 

Expected behavior:

• Implementation/exposure of FocusedItemStyle
• Left and right keyboard arrows should move focus spatially inside the grid; if RadListView is in 1-column (list) mode, Left == Up, Right == Down

Further suggestions:

• Implementation/exposure of HoverItemStyle, for when the mouse pointer is over an item cell
• (changed) ScrollItemIntoView(object item, boolean focusItemAfterScroll, boolean selectItemAfterScroll)
• (new) FocusItem(object item) 
• (new) SelectItem(object item) 

Hello, could you provide some guidance about the following situation....

I have a scenario using the RadListView that implements a PropertyGroupDescriptor for a property attached to my ObservableCollection<T>, where the property that it is monitoring is string value.  The dataset is designed that it may have only one grouping before an item is selected them the dataset will have two different groupings.  One the data changes, the ListView updates to show that there are two different groups but the group header doesn't change and neither does the cell content.  If I click on the GroupHeader of the new section, then it updates to reflect the change in data.  Is there a way to get the data to change in the Listview with some kind of Refresh so it stays up to date with the data.

Seeing it on iOS right now.

Thanks

Telerik RadListView with two Columns - they are Thumbnails with a tap gesture. When we change the Spancount to 1 there is no right border line but when set back to 2 it shows as the screenshot on IOS, 

The issue happens on iPhone 11, XR, devices with a notch, and when ListViewGridLayout is with SpanCount="2".

Workaround: Set the background color of the ListViewItemStyle to Transparent

<telerikDataControls:RadListView.ItemStyle>
    <telerikListView:ListViewItemStyle BorderWidth="0" 
                                        BackgroundColor="Transparent"/>
</telerikDataControls:RadListView.ItemStyle>

This is from our production app. Cannot reproduce it, don't know exactly when or why it happens; we just have crashes logged to have happened to 9 users in the past year with a total of 30 occurences.

These are unhandled UWP exceptions, which mean that our app goes poof :)

System.ArgumentException: Value does not fall within the expected range at
System.ThrowHelper.ThrowAddingDuplicateWithKeyArgumentException(Object) + 0xf     at
Telerik.UI.Xaml.Controls.Data.ListView.Model.BaseLayoutStrategy.RecycleLocally() + 0x320     at Telerik.UI.Xaml.Controls.Data.ListView.Model.BaseLayoutStrategy.MeasureContent(RadSize, Double, Double) + 0xd     at Telerik.UI.Xaml.Controls.Data.ListView.Model.LayoutController.MeasureVertical(RadSize) + 0x1b9     at Telerik.UI.Xaml.Controls.Data.ListView.Model.LayoutController.MeasureContent(RadSize) + 0x42     at Telerik.UI.Xaml.Controls.Data.ListViewModel.MeasureContent(RadSize) + 0x2e     at Telerik.UI.Xaml.Controls.Data.RadListView.OnContentPanelMeasure(RadSize) + 0x17f     at Telerik.UI.Xaml.Controls.Data.ListView.ListViewPanel.MeasureOverride(Size) + 0x60     at Windows.UI.Xaml.FrameworkElement.global::Windows.UI.Xaml.IFrameworkElementOverrides.MeasureOverride(Size) + 0x26

System.ArgumentException: An item with the same key has already been added    at
System.ThrowHelper.ThrowAddingDuplicateWithKeyArgumentException(Object) + 0xf     at Telerik.UI.Xaml.Controls.Data.ListView.Model.BaseLayoutStrategy.RecycleLocally() + 0x320     at Telerik.UI.Xaml.Controls.Data.ListView.Model.BaseLayoutStrategy.MeasureContent(RadSize, Double, Double) + 0xd     at Telerik.UI.Xaml.Controls.Data.ListView.Model.LayoutController.MeasureVertical(RadSize) + 0x1b9     at Telerik.UI.Xaml.Controls.Data.ListView.Model.LayoutController.MeasureContent(RadSize) + 0x42     at Telerik.UI.Xaml.Controls.Data.ListViewModel.MeasureContent(RadSize) + 0x2e     at Telerik.UI.Xaml.Controls.Data.RadListView.OnContentPanelMeasure(RadSize) + 0x17f     at Telerik.UI.Xaml.Controls.Data.ListView.ListViewPanel.MeasureOverride(Size) + 0x60     at Windows.UI.Xaml.FrameworkElement.global::Windows.UI.Xaml.IFrameworkElementOverrides.MeasureOverride(Size) + 0x26

When applying multi-level grouping, then change the items group keys, the new groups are added but the old ones are still visible in the list view, and from child group they become parent group. 

Workaround:

clear the group descriptors before changing the items and then re-add the group descriptors again