DiagramBase.NodeSelecting Event

Raised when the user tries to select a node, this event lets you cancel the operation.

Namespace: MindFusion.Diagramming
Assembly: MindFusion.Diagramming

 Syntax

C#

public event EventHandler<NodeValidationEventArgs> NodeSelecting

Visual Basic

Public Event NodeSelecting As EventHandler(Of NodeValidationEventArgs)

 Event Data

NodeSelecting event handlers receive an argument of type NodeValidationEventArgs. The following NodeValidationEventArgs members provide information relevant to the event:

Member name	Description
Node	The DiagramNode that the user is trying to select.
MousePosition	A Point specifying the mouse cursor position.
SelectionRectangle	The current selection rectangle.

 Remarks

NodeSelecting is raised in two distinct cases - when the user clicks a node, or while the user is drawing a selection rectangle. When raised because of a mouse click, the MousePosition argument is set to a valid point and the SelectionRectangle argument equals to Empty. While the user is drawing a selection rectangle, the event is raised for each mouse movement, the SelectionRectangle contains the selection coordinates and the MousePosition parameter equals to Empty.

NodeSelecting is raised while enumerating all items in the z-order collection, so you cannot change the node's ZIndex while handling this event. A selection-related event suitable for changing the z-order of items is SelectionChanged.