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DockLayoutManager.DockItemStartDocking Event

Fires when a docking operation starts, and allows you to prevent this operation.

Namespace: DevExpress.Xpf.Docking

Assembly: DevExpress.Xpf.Docking.v21.2.dll


public event DockItemCancelEventHandler DockItemStartDocking

Event Data

The DockItemStartDocking event's data class is ItemCancelEventArgs. The following properties provide information specific to this event:

Property Description
Cancel Gets or sets whether the current operation must be canceled.
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.
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.


End-users can perform docking operations by pressing a dock panel’s caption with the mouse and dragging it. Once a docking operation starts, the DockItemStartDocking event fires. To prevent panels from being docked, handle the DockItemStartDocking event and set the event’s Cancel parameter to true.

It’s also possible to prevent a dock item from being docked by setting the BaseLayoutItem.AllowDock property to false.

See Also