I have a situation where I have 2 XamDataTrees that I need to be able to drag and drop items from one to the other.
Data structure consists of Schemas, Groups, Nodes, Leaves:
What we want to achieve with dragging:
Since the tree is particular about the type when dragging and dropping, this is proving to be a challenging problem. Deriving from a base type gets things working, but I can't disallow things like dragging a node from Tree 2 into a schema in Tree 1. This seems to be a problem of the IsDropTarget being conditional on what the drag source type is and I can't figure out how to make that happen with this control. Any help would be appreciated.
Hello Tracie,
I have been investigating into your requirement, and at the moment, none of the drag-drop related events that the XamDataTree exposes will really let you restrict drag and drop from one node to another, especially if they are all derived from a base type and the collections that make up your layout are child collections of that base type as you have mentioned.
With that said, some time ago I did derive a solution for another forum thread discussion using the IsEnabledMemberPath of the NodeLayout and the NodeDraggingStart and NodeDragEnd events so that you can disable certain underlying data items from being dragged to depending on the type that you are currently dragging. That forum thread, along with a sample project I wrote for it is located here: https://es.infragistics.com/community/forums/f/retired-products-and-controls/105253/xamdatatree-drag-drop-within-the-parent-node. Please disregard the mentioning of the “Silverlight” XamDataTree, as the XamDataTree was a shared control between Silverlight and WPF, back when we still supported Silverlight.
By setting the underlying property that the IsEnabledMemberPath is pointed at such that some nodes will be disabled, your end user will not be able to drag to the nodes that are disabled. The same can be said from Tree 1 to Tree 2 in this case if you mark the IsEnabledMemberPath for all of the items in Tree 2 to be disabled when a node begins dragging in Tree 1. Then, you can reset the underlying IsEnabledMemberPath property in the NodeDragEnd event.
I hope this helps you. Please let me know if you have any other questions or concerns on this matter.
Hi Andrew,
Thanks for the reply.
The thread that you pointed me to isn't terribly helpful because the NodeDraggingStart event doesn't appear to know at any point what the droptarget will be. What I really need is the ability to disable the droptarget dependent on the types for both the dragsource and the droptarget.
With that said, I was able to get something kind of working through the NodeDragDrop event. I look for the type on both the dragnode and the droptarget, then set
e.DragDropEventArgs.OperationType = Infragistics.DragDrop.OperationType.DropNotAllowed; e.Handled = true;
This seems to work, the only issue at this point is the styling of the cursor as it hovers over the droptarget. It indicates that a drop should be possible, but this logic disables it. Any clues on how I can restyle the template?