Listbox DragDrop inside TileView

[Wenrong]

Please find the sample project here

The sample application is divided into two parts:

The bottom part is similar to the RadListBox drag-n-drop demo with 4 elements:

1. RadListBox bound to ObservableCollection<Country> CountryList
2. RadListBox bound to ObservableCollection<Country> GroupA
3. RadListBox bound to ObservableCollection<City> GroupD
4. WPF ListBox bound to ObservableCollection<Country> GroupA, AllowDrop unset
   

The Drag-n-Drop behaviour is as expected, I can drag n drop between 1&2, but not to 3 or 4, it worked very well.

The top part is the identical setup, except it is contained within a RadTileView, and there are a few unexpected behaviours:

1. Cursor no longer change to Cursors.No when drag over list 3 & 4
2. When dropped on list 3, nothing happens, this is good. But when dropped on list 4 or anywhere on the tileview that's not a RadListBox, the item is removed from the drag source, and not added to anywhere.

So how do I fix these two issues?

[Zarko]

Hello Wenrong,
Thank you for the feedback and I'll try to answer your questions:
- this is an issue in the RadTileView and it will be fixed in some of our next releases
- the problem is that the RadTileView is also listening for Drop events and that's why you items disappear.
You can workaround both of your problems with this code:

private bool isTileViewDrag = false;

public MainWindow()
{
    InitializeComponent();

    DragDropManager.AddDragInitializeHandler(this.tileView, OnDragInit);
    DragDropManager.AddGiveFeedbackHandler(this.tileView, OnGiveFeedback);
}

private void OnGiveFeedback(object sender, Telerik.Windows.DragDrop.GiveFeedbackEventArgs e)
{
    if (!this.isTileViewDrag)
    {
        e.Handled = true;
        e.UseDefaultCursors = true;
    }
}

private void OnDragInit(object sender, DragInitializeEventArgs e)
{
    var container = e.OriginalSource as RadTileViewItem;
    if (container != null)
    {
        this.isTileViewDrag = true;
        this.tileView.AllowDrop = true;
    }
    else
    {
        this.isTileViewDrag = false;
        this.tileView.AllowDrop = false;
    }
}

If you have further questions please feel free to ask.

All the best,
Zarko
the Telerik team