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Initialization, state and notifications#

The following methods and properties of DisplayPluginViewModel provide display initialization, state and notifications

  • Display initialization
    • OnInitialised()
      • Called when display is first initialized (programmatic parameters should ideally be added within this override)
  • Display state properties
    • ActiveCompositeSessionContainer
      • Access to compare set associated with display (can be null if no association)
    • ServiceContext
      • Access to per display services
    • IsSelected
      • True when page is active and display is shown, false when display is overlaid by another display
    • CanRetrieveData
      • False when display is inactive or no session is associated and therefore display should not retrieve data
    • ScopeIdentity
      • Unique identity of display (mainly used to associate results of a data request to a display)
  • Display change notifications
    • OnActiveDisplayPageChanged(bool isActive)
      • Called whenever page is switched (isActive is true when the active page contains the display)
    • OnCanRenderDisplayChanged(bool canRender)
      • Called whenever display visibility changes (canRender is true when display is visible)


CanRetrieveData should be used exclusively for deciding whether it is necessary to make data requests.


Do NOT access ActiveCompositeSessionContainer when CanRetrieveData is false, as an unexpected exception may be raised