DockLayoutManager.DockItemClosing Event
Fires before a dock item is closed (hidden), and allows you to prevent this action.
Namespace: DevExpress.Xpf.Docking
Assembly: DevExpress.Xpf.Docking.v21.1.dll
NuGet Package: DevExpress.Wpf.Docking
Declaration
Event Data
The DockItemClosing 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. |
Remarks
To prevent a dock item from being closed (hidden), set the event’s Cancel parameter to true, or set the BaseLayoutItem.AllowClose option to false. After an item has been closed, the DockLayoutManager.DockItemClosed event fires.
Closed items can be accessed via the DockLayoutManager.ClosedPanels collection.
The currently closed dock item is specified by the event’s Item parameter.
Floating panels are created with the help of float groups. If a float group contains a single panel, a single close (‘x’) button exists there:
Clicking this button closes the float group, hiding the nested dock panel. The DockItemClosing event fires only for the float group object. To access the dock panel nested within the float group, see the float group’s LayoutGroup.Items collection.
If a float group contains two or more panels, the ‘x’ button is displayed for the float group, and all its nested panels:
Again, clicking the ‘x’ button for the float group fires the DockItemClosing event for the float group object. If the ‘x’ button is clicked for panels, the DockItemClosing event fires with the Item parameter referring to the corresponding panel.
Related GitHub Examples
The following code snippet (auto-collected from DevExpress Examples) contains a reference to the DockItemClosing event.
Note
The algorithm used to collect these code examples remains a work in progress. Accordingly, the links and snippets below may produce inaccurate results. If you encounter an issue with code examples below, please use the feedback form on this page to report the issue.