DockLayoutManager.DockItemDocking Event
Fires before a dock item is dragged over dock hints, and allows you to prevent dock zones from being displayed.
Namespace: DevExpress.Xpf.Docking
Assembly: DevExpress.Xpf.Docking.v20.2.dll
NuGet Packages: DevExpress.WindowsDesktop.Wpf.Docking, DevExpress.Wpf.Navigation
Declaration
Event Data
The DockItemDocking event's data class is DockItemDockingEventArgs. The following properties provide information specific to this event:
| Property | Description |
|---|---|
| Cancel | Gets or sets whether the current operation must be canceled. Inherited from ItemCancelEventArgs. |
| DockTarget | Gets the item to which the current item is being docked. |
| DockType | Gets how an item is being docked to another item. |
| DragPoint | Gets the point at which the item is being docked. The point is relative to the top left corner of the target item’s root parent. |
| 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 RoutedEventArgs. |
| IsHiding | Gets whether the item is being docked over a zone used to set the item to the auto-hide state. |
| Item | Gets the currently processed item. Inherited from ItemEventArgs. |
| OriginalSource | Gets the original reporting source as determined by pure hit testing, before any possible Source adjustment by a parent class. Inherited from RoutedEventArgs. |
| RoutedEvent | Gets or sets the RoutedEvent associated with this RoutedEventArgs instance. Inherited from RoutedEventArgs. |
| Source | Gets or sets a reference to the object that raised the event. Inherited from RoutedEventArgs. |
The event data class exposes the following methods:
| Method | Description |
|---|---|
| InvokeEventHandler(Delegate, Object) | 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 RoutedEventArgs. |
| OnSetSource(Object) | 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 RoutedEventArgs. |
Remarks
When an end-user is dragging a panel, visual hints appear, helping an end-user to decide where to dock the panel. When hovering over a hint, the potential dock zone is painted in the background, and this indicates where the panel will be docked if dropped. The DockItemDocking event fires repeatedly when hovering over any visual marker. If the event’s Cancel parameter is set to true, the potential dock zone is not painted. Note that this doesn’t prevent the panel from being dropped at this position. To prevent a panel from being dropped at a specific position, handle the DockLayoutManager.DockItemEndDocking event.
It’s also possible to prevent an item from being docked by setting the BaseLayoutItem.AllowDock property to false.