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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.v22.1.dll

NuGet Package: DevExpress.Wpf.Diagram

Declaration

public event EventHandler<DiagramQueryItemsActionEventArgs> QueryItemsAction

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.

See Also