Get Old and New Parent of a Task after Reordering via Drag and Drop

Updated on Sep 15, 2025

Environment

Product Version	2019.1 318
Product	RadGanttView for WPF

Description

How to acquire the old and new parent of a task after reorder via drag and drop.

Solution

For the purpose you can define a custom GanttDragDropBehavior and override its Drop method as follows:

C#

  	protected override void Drop(SchedulingDragDropState state)
  	{
		var task = state.DraggedItem as GanttTask;
		var item = this.Gantt.ExpandCollapseService.HierarchicalCollectionAdapter.GetItemWrapperByItemKey(task);
		var previousParent = item.Parent;
		base.Drop(state);
		var newItem = this.Gantt.ExpandCollapseService.HierarchicalCollectionAdapter.GetItemWrapperByItemKey(task);
		var newParent = newItem.Parent;
  	}

See Also

• Custom GanttDragDropBehavior