TreeList.DragObjectStart Event

Fires when an end-user attempts to drag a column header.

Namespace: DevExpress.XtraTreeList

Assembly: DevExpress.XtraTreeList.v19.1.dll

Declaration

C#

public event DragObjectStartEventHandler DragObjectStart

VB.NET

Public Event DragObjectStart As DragObjectStartEventHandler

Event Data

The DragObjectStart event's data class is DevExpress.XtraTreeList.DragObjectStartEventArgs.

Remarks

The following events enable you to control dragging column headers:

• The DragObjectStart fires when an end-user tries to drag a column header. You can handle the event to prevent header dragging. (You can also disable column header dragging using the TreeListOptionsColumn.AllowMove option.)
• The TreeList.DragObjectOver event fires repeatedly while dragging the object. The event allows you to prevent dropping while over an inappropriate area.
• The TreeList.DragObjectDrop fires immediately after a drag and drop operation has been completed. The event serves as a notification only and does not allow you to prevent dropping.

When handling the DragObjectStart event, use the DragObject parameter to identify the column whose header is about to be dragged. To prevent a drag and drop operation, set the Allow parameter to false.