Drag and Drop with Multiple selection

[Audrey]

Hi,

I used a Listbox with a WrapPanel in an ItemsPanelTemplate, like this :

<ListBox x:Name="ProgrammingBox" SelectionMode="Extended">
      <ListBox.ItemsPanel>
               <ItemsPanelTemplate>
                    <toolkit:WrapPanel  />
              </ItemsPanelTemplate>
       </ListBox.ItemsPanel>
</ListBox>

I used the RadDragAndDropManager.

And I want to Drag and Drop multiple items into my Listbox to reorder them. I use the Shift key to select them, but I must stay clicked on my selection to Drag and Drop it. Is it a normal behavior ? Is there a solution to release the mouse click between the selection and the drag and drop ?

Audrey

[Tsvyatko]

Hello Audrey,

As I understand, the issue you are facing is the fact that in extended mode, the listbox select/unselects its items onmousedown (rather than onmouseup). As a result drag drop operations could be performed only on single item.

So, in order to enable dragging multiple items I can suggest to try trigger the drag operation manually:

 - Save and update the selected items on mouseleftbuttonUp
 - On MouseLeftButtonDown subscribe to mousemove
 - if it exceeds the initial threshold (4 pixels is its default value) while dragging start drag using RadDragAndDropManager.StartDrag


All the best,
Tsvyatko
the Telerik team

[Audrey]

Thank you for your help !

[Guillaume]

Hello,

Please, can you attach a solution to understand ?

Regards,
Guillaume

[Brian Chung]

Hello Tsvyatko,

 

Do you have a sample code for this DragDrop with multiple selection in list box? Thanks!

Brian.

[Dimitrina]

Hello,

As it turns out we do not have such an exact example. You can refer to the TreeToGrid online demo as well as other demos and documentation on DragDropManager. 

In order to drag and drop multiple rows you have to loop through the selected items of the source ListBox and save information on all the dragged items with dragPayload on DragInitialize (through DropIndicationDetails). Basically, you should replace the CurrentDraggedItem property with the collection of items being dragged. Then, get the saved details on drop to proceed further.

Regards,
Dimitrina
Telerik