Drag/Drop with ItemsSource set to ListCollectionView

[Martin]

Hello,

I am having trouble enabling drag/drop functionality in a RadTreeView when I set its ItemsSource to a ListCollectionView. Here is an example:

<Window x:Class="WpfApplication6.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:Telerik="http://schemas.telerik.com/2008/xaml/presentation"
    SizeToContent="WidthAndHeight"
    Title="Window1">
    <Telerik:RadTreeView x:Name="sourceTree" Height="300" Width="300" IsDragDropEnabled="True"/>
</Window>

    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();

            ObservableCollection<string> testCollection = new ObservableCollection<string>();
            testCollection.Add("one");
            testCollection.Add("two");
            testCollection.Add("three");

            ListCollectionView view = new ListCollectionView(testCollection);
            sourceTree.ItemsSource = view;
        }
    }

The items display fine, but when I drag and drop them nothing seems to happen. If I set the ItemsSource directly to the testCollection, it works just fine, but I need to use a ListCollectionView in my case in order to enable filtering. Is this a bug in the control, or am I doing something improperly? Thanks.

[Tihomir Petkov]

Hello Martin,

RadTreeView needs a collection for its ItemsSource property in order to function correctly and that is why the drag and drop stops working when you set the ItemsSource to be your ListCollectionView. What you can do in your case though, is use the default view of your collection. You can do so as follows:

sourceTree.ItemsSource = testCollection;
ListCollectionView view = (ListCollectionView)CollectionViewSource.GetDefaultView(sourceTree.ItemsSource);

Let me know if this solves your problem.

All the best,
Tihomir Petkov
the Telerik team

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[Martin]

Hi Tihomir,

Your solution is exactly what I was looking for. Thanks for the reply!

Martin