Autoscroll while drag & drop not working (again)

[Carlos Serrano]

Hello!

We just migrated from a one-year-old version of the Silverlight RadControls to the latest (2013.1.0220), and we noticed that the RadTreeView does not autoscroll anymore when we drag and drop items.

It seems to be an issue that came up a few times during the lifetime of the RadControls so it is worrisome to see it again.

As a note, we still use the obsoleted RadDragAndDropManager (since the newest DragDropManager would require a substantial rewrite on our end). The demo at http://demos.telerik.com/silverlight/#TreeView/DragDrop also exhibits the same problem (and it also uses the RadDragAndDropManager).

Would it be possible to have a hotfix for this?

Thanks,
Carlos.

[Tina Stancheva]

Hello Carlos,

As you correctly noted the RadTreeView is currently using the obsolete RadDragAndDropManager to implement its built-in drag/drop logic. However, during this release cycle will update the implementation of the control to take advantage of the new DragDropManager - you can track the progress of this task in our PITS. Once we do that, we will make sure to address the AutoScrolling issue as well.

In the meantime we created a sample auto-scroll behavior that you can attach to the RadTreeView control. Please take a look at this blog post further describing this solution and let us know if it can work for you.

Regards,
Tina Stancheva
the Telerik team

[Carlos Serrano]

Hello,

I confirm that the workaround on the blog post works, albeit not as well as the original code (it seems to be missing some fine-tuning, as the autoscrolling is not as precise).

I noticed on the PITS that the version for Q2 2013 is now able to use the new drag & drop manager. But I also wanted to check with you if we could also use the old drag and drop manager with that release, and whether that issue I mentioned has been fixed for Q2 2013?

Thanks,
Carlos.

[Tina Stancheva]

Hello Carlos,

We implemented the new RadTreeView DragDrop logic (using the DragDropManager) with the Q1 2013 SP1 release. However, we're still fine-tuning it and if you'd like to test it, you can do so using the latest internal build. Basically in order to work with the new DragDropManager logic implemented within the RadTreeView, you need to set the TreeViewSettings.DragDropExecutionMode attached property to New:

<telerik:RadTreeView IsDragDropEnabled="True"
             ItemTemplate="{StaticResource ItemTemplate}"
             ItemsSource="{Binding Items}"
             telerik:TreeViewSettings.DragDropExecutionMode="New" />

The official and final version of the updated DragDropManager logic will be available with the Q2 2013 release as you correctly noted. It will include auto-scrolling out-of-the-box. And if you'd like to test the auto-scrolling behavior you can do so in the sample I attached.

However, please note that even though you will still be able to use the old DragAndDropManager logic in the control, we will eventually remove it. This is why we haven't included any changes in it and it won't support auto-scrolling during drag out-of-the-box. And we strongly recommend updating your RadTreeView implementation to use the new dragging logic at your earliest convenience after the Q2 2013 release is out. The DragDropManager provides a better flexibility of the RadTreeView dragging operations and you'll be able to easily customize them in case they don't completely work per your requirements.

Kind regards,
Tina Stancheva
the Telerik team