Set to true in a EntityViewerComponent.BeforeViewTypeChange handler to veto the switch.
The descriptor DriverClass / Name being switched to (e.g. "ClusterViewType").
The MJ: View Types row ID being switched FROM (null on the first selection).
The MJ: View Types row ID being switched to.
Event payload for the view-type change lifecycle. Emitted (cancelable) via EntityViewerComponent.BeforeViewTypeChange and (notification) via EntityViewerComponent.AfterViewTypeChange. A handler may set
Cancel = trueon the Before event to veto the switch (mirrors the grid'sBeforeRowClick/BeforeCellEditcancelable pattern).