DiagramControl.QueryItemsAction Event
Fires each time the DiagramControl queries whether an action can be performed on specific diagram items.
Namespace: DevExpress.Xpf.Diagram
Assembly: DevExpress.Xpf.Diagram.v23.2.dll
NuGet Package: DevExpress.Wpf.Diagram
Declaration
Event Data
The QueryItemsAction event's data class is DiagramQueryItemsActionEventArgs. The following properties provide information specific to this event:
| Property | Description |
|---|---|
| Action | Indicates the queried action. |
| Allow | Specifies whether to allow performing the operation. |
| 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. |
| HighlightedItem | Returns the currently highlighted diagram item. |
| HighlightedItemPoint | Returns the current coordinates of the cursor. |
| Items | Returns the collection of queried diagram items. |
| 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
The DiagramControl fires the QueryItemsAction event to configure the appearance of visual elements such as adorners and the cursor type. It is not recommended to use the QueryItemsAction event to track the user actions.
The event’s Items property returns the collection of queried diagram items. The Action property returns the queried action.
Set the Allow property to false to restrict the action.