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Diagram Events

This topic covers the specific events exposed by the RadDiagram. The events are grouped by their general purpose.

Selection Events

  • PreviewSelectionChanged - occurs when the selection of the diagram starts changing.

  • SelectionChanged - occurs when the selected item/items are changed.

  • SelectionBoundsChanged - occurs when the selection adorner rectangle is changed.

Resizing Events

  • PreviewResize - occurs when item/items is/are about to be resized.

  • Resize - occurs when item/items is/are resized.

Rotation Events

  • PreviewRotate - occurs when item/items is/are about to be rotated.

  • Rotate - occurs when item/items is/are rotated.

Drag Events

  • PreviewDrag - occurs when dragging operation is about to be performed.

  • Drag - occurs when dragging operation is performed.

Serialization Events

  • Deserialized - occurs when deserialization process end.

  • Serialized - occurs when serialization process end.

  • ShapeDeserialized - occurs when shape is deserialized.

  • ShapeSerialized - occurs when shape is serialized.

  • ConnectionDeserialized - occurs when connection is deserialized.

  • ConnectionSerialized - occurs when connection is serialized.

  • MetadataDeserialized - occurs when metadata is deserialized.

  • MetadataSerialized - occurs when metadata is serialized.

Click Events

  • ShapeClicked - occurs when shape is clicked.

  • ShapeDoubleClicked - occurs when shape is double clicked.

Command Events

  • CommandExecuted - occurs when DiagramCommand is executed.

Items Collection Events

  • ItemsChanging - occurs while the Items collection is changing its items.

  • ItemsChanged - occurs when Items collection is changed.

Connection Manipulation Events

  • ConnectionManipulationStarted - event that is raised by a RadDiagram to inform that a connection manipulation is starting.

  • ConnectionManipulationCompleted - event that is raised by a RadDiagram to inform that a connection manipulation is ending.

When you manipulate a connection you have two different stages of the process - start of the manipulation and end of the manipulation. When you start manipulating a connection - for instance creating a new connection or detaching a connection, the ConnectionManipulationStarted event is fired. When the manipulation is in its ending stage - the ConnectionManipulationCompleted event is fired. And it is important to work with both events in order to cover all parts of a single connection manipulation. And it is also very crucial to note that both events are designed to represent preview events and their purpose is to allow you to cancel a connection manipulation.

This means that the ConnectionManipulationStarted event is fired before the manipulation of a connection is truly started - in this case the EventArgs (e) of the event hold the e.Connection that is going to be manipulated (or created), and the e.Shape and the e.Connector that are part of the manipulation. In case you're starting to drag a new connection out of the connector of a shape, then the ConnectionManipulationStarted will be fired before the connection is created. This way you can cancel the process and therefore the e.Connection property will be null, while the e.Shape and e.Connector properties will hold the shape and the connector where the drag is originating from. And if you're detaching a connection, again you'll have to handle the ConnectionManipulationStarted event as you're starting a new manipulation of a connection. When detaching a connection, the e.Connection property will reflect the connection that is being detached and the e.Shape property will reflect the shape from which the connection is detached. However, please note that in this case the e.Shape IncomingLinks/OutgoingLinks collections will still hold a reference of the current connection as the ConnectionManipulationStarted event is a preview event and when it is fired, the connection isn't really detached yet.

The same logic applies for the ConnectionManipulationCompleted event - it is fired just before a connection manipulation is over - for example when attaching a connection to a shape. Again you'll have a reference of the e.Connection that is being attached and the e.Shape to which the connection will be attached, but at this point the connection is still not attached and therefore its SourceShape/TargetShape properties are not updated.

The arguments of both events expose a ManipulationStatus property. It serves as an indicator for the status of the current connection manipulation. This property is an enumeration that provides the following members:

  • Attaching - represents the status of a connection that is currently being attached to a shape. This is the status indicated by a ConnectionManipulationStarted event when a connection is created by dragging it out of a connector or in a ConnectionManipulationCompleted when a connection is being attached to a new connector.

  • Detaching - represents the status of a connection that is currently being detached from a shape. Please note that this status can only be indicated by a ConnectionManipulationStarted event as the detaching of a connection can only be in the beginning of a manipulation.

  • Moving - represents the status of a connection that is currently being moved. Usually this is a status indicated by a ConnectionManipulationStarted while moving a floating connection.

  • Moved - represents the status of a connection that was moved. Usually this is a status indicated by a ConnectionManipulationCompleted event fired after releasing the mouse to create a floating connection.

Layout Events

  • DiagramLayoutComplete - occurs when the Layout operation has completed.

Grouping Events

  • GroupsChanged - occurs when the root level logical group is created or ungrouped.

Pan and Zoom Events

  • PositionChanged - fires when the position of the diagram is changed.

  • ViewportChanged - fires when the viewport of the diagram is changed.

  • ZoomChanged - fires when a zoom operation has been performed.

Container Generation Events

  • VisualChildrenChanged - occurs when a visual object (RadDiagramShape or RadDiagramConnection) is added or removed in the ItemsHost of the Diagram.

  • GraphSourceChanged - occurs when the GraphSource is changed and all DiagramItems are properly measured.

  • GraphSourceChanging - Occurs when the GraphSource starts changing.

AdditionalContent Events

  • PreviewAdditionalContentActivated - this event is raised by a RadDiagram to inform layouts that the additional content is going to be activated. The event handler receives two arguments:

    • The sender argument contains the RadDiagram This argument is of type object, but can be cast to the RadDiagram type.

    • An AdditionalContentActivatedEventArgs object, that gives you access to a ContextItems collection. This collection of IDiagramItem objects represents the items that have activated the additional content. In most cases it contains a single item - the RadDiagramItem that has activated the SettingsPane.

    Please note that you can handle this event in order to disable the AdditionalContent (SettingsPane) from displaying on certain RadDiagramItems.

  • AdditionalContentActivated - this event is raised by a RadDiagram to inform layouts that the additional content has been activated. The event handler receives two arguments:

    • The sender argument contains the RadDiagram This argument is of type object, but can be cast to the RadDiagram type.

    • An AdditionalContentActivatedEventArgs object, that gives you access to a ContextItems collection. This collection of IDiagramItem objects represents the items that have activated the additional content. In most cases it contains a single item - the RadDiagramItem that has activated the SettingsPane.

See Also