You will be able to achieve the desired by using our DragDropManager
- in the drop handler of the second ListBox you will need to check whether there is an item in its ItemsSource with the same ID. If so you will have change the quantity as needed or if there isn't such an item to manually add it. For more details on how to achieve such a drag drop functionality between two ListBoxes you can check the following article from our online help documentation:
The Drop handler should be implemented as demonstrated below:
sender, Telerik.Windows.DragDrop.DragEventArgs e)
var data = DragDropPayloadManager.GetDataFromObject(e.Data,
var destinationItemsSource = (sender
var item = destinationItemsSource.FirstOrDefault(x => x.ID == data.ID);
item.Quantity += data.Quantity;
Please give it a try and if you have any further questions, let us know.
Hope this helps.
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