DropPosition Enumeration

You can set a drop position that specifies:

• How to place the drop marker concerning a target record.
• How to place the dragged record after dropping.

The values listed by the DropPosition enumeration are used to set the DragEventArgsBase.DropPosition and DropMarkerData.Position properties.

The image below shows a drag-and-drop operation that does not allow moving a node to another child collection; it means the DropPosition.Inside is not allowed:

Handle the DataViewBase.DragRecordOver event and specify the DragEventArgsBase.DropPosition property to set the required drop position. The following code sample demonstrates how to prohibit end-users from moving nodes to another node's child collection:

<dxg:TreeListView AllowDragDrop="True" DragRecordOver="OnDragRecordOver" /> 

void OnDragRecordOver(object sender, DragRecordOverEventArgs e) {
   if(e.DropPosition == DropPosition.Inside) {
      e.DropPosition = e.DropPositionRelativeCoefficient > 0.5 ? DropPosition.After : DropPosition.Before;
      e.Handled = true;
   }
}

In the demonstrated code sample, the DragRecordOverEventArgs.DropPositionRelativeCoefficient property is used to determine the exact drop position.