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Let's say I have some collection of data. My goal is to provide different kind of view of ItemsControl depending on user`s preference. For simplicity, we can assume that user can select only betwe...
#1: Initial revision
How to dynamically change panel of ItemsControl?
Let's say I have some collection of data. My goal is to provide different kind of view of `ItemsControl` depending on user`s preference. For simplicity, we can assume that user can select only between two states - horizontal & vertical. MCVE ```csharp public enum ViewType { H, V } public class MainWindowViewModel : ViewModelBase { private ViewType _viewType; public MainWindowViewModel() { Values = Enumerable.Range(0, 20).Select(v => v.ToString()); ViewTypes = new[] { ViewType.H, ViewType.V }; ViewType = ViewTypes[0]; } public ViewType ViewType { get => _viewType; set => this.RaiseAndSetIfChanged(ref _viewType, value); } public IEnumerable<string> Values { get; } public ViewType[] ViewTypes { get; } } ``` ```xml <Grid RowDefinitions="*,Auto"> <ItemsControl Items="{Binding Values}" Grid.Row="0" /> <ComboBox Items="{Binding ViewTypes}" Grid.Row="1" SelectedItem="{Binding ViewType}"/> </Grid> ``` But I wasn't able to find a way to define selector for `ItemsPanelTemplate`. ---- When I tried to use converter: ```xml ItemsPanel="{Binding ViewType, Converter={StaticResource ResourceKey=converter}}" ``` ```csharp public class ViewTypePanelConverter : IValueConverter { public object Convert(object value, Type targetType, object parameter, CultureInfo culture) { var template = new ItemsPanelTemplate() { Content = new Func<IServiceProvider, ControlTemplateResult>( _ => { var content = value switch { ViewType.V => new StackPanel { Orientation = Orientation.Vertical }, ViewType.H => new StackPanel { Orientation = Orientation.Horizontal }, _ => throw new NotImplementedException(), }; return new ControlTemplateResult(content, new NameScope()); }) }; return template; } public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture) { throw new NotImplementedException(); } } ``` it has zero effect. ---- This Q is inspired by [Use DataTemplate for `ItemsControl.ItemsPanel` #7268](https://github.com/AvaloniaUI/Avalonia/discussions/7268) discussion from [`Avalonia`](https://github.com/AvaloniaUI/Avalonia) project repo.