TreeViewControl.StartRecordDrag Event
In This Article
Occurs when a drag-and-drop operation is started.
Namespace: DevExpress.Xpf.Grid
Assembly: DevExpress.Xpf.Grid.v24.2.dll
NuGet Package: DevExpress.Wpf.Grid.Core
#Declaration
public event EventHandler<StartRecordDragEventArgs> StartRecordDrag
#Event Data
The StartRecordDrag event's data class is StartRecordDragEventArgs. The following properties provide information specific to this event:
Property | Description |
---|---|
Allow |
Gets or sets whether an end-user can drag records. |
Allowed |
Gets a member of the Drag |
Data |
Gets or sets a data object that contains the data associated with the Data |
Drag |
Gets a drag element that is a control on which the drag-and-drop operation has been initiated. |
Handled |
Gets or sets a value that indicates the present state of the event handling for a routed event as it travels the route.
Inherited from Routed |
Original |
Gets the original reporting source as determined by pure hit testing, before any possible Source adjustment by a parent class.
Inherited from Routed |
Records | Gets dragged records. |
Routed |
Gets or sets the Routed |
Source |
Gets or sets a reference to the object that raised the event.
Inherited from Routed |
The event data class exposes the following methods:
Method | Description |
---|---|
Invoke |
When overridden in a derived class, provides a way to invoke event handlers in a type-specific way, which can increase efficiency over the base implementation.
Inherited from Routed |
On |
When overridden in a derived class, provides a notification callback entry point whenever the value of the Source property of an instance changes.
Inherited from Routed |
#Remarks
You can use the StartRecordDrag event to cancel a drag operation.
The following code sample allows users to drag only records that do not have children:
<dxg:TreeViewControl x:Name="treeview"
AllowDragDrop="True"
StartRecordDrag="treeview_StartRecordDrag"/>
void treeview_StartRecordDrag(object sender, DevExpress.Xpf.Core.StartRecordDragEventArgs e) {
foreach (Employee employee in e.Records)
e.AllowDrag = !treeview.GetNodeByValue(employee.Name).HasChildren;
e.Handled = true;
}
For information about drag-and-drop operations, refer to the following DevExpress WPF Grid help topic: Drag-and-Drop.
See Also