TCustomListView checks IsCustomDrawn to determine when to generate the OnCustomDraw, OnAdvancedCustomDraw, OnCustomDrawItem, OnAdvancedCustomDrawItem, OnCustomDrawSubItem, and OnAdvancedCustomDrawSubItem events. IsCustomDrawn returns true when the list view should generate an event. 

The Target parameter indicates whether the list view is about to draw the entire control, an item, or a subitem. IsCustomDrawn does not return true unless the list view has an appropriate event handler for the target. 

The Stage parameter indicates the current stage in the process of painting the list view. IsCustomDrawn returns true if the stage is cdPrePaint or if there is an Advanced custom draw event handler for the Target. 

OnCustomDraw 

OnCustomDrawItem 

OnCustomDrawSubItem 

OnAdvancedCustomDraw 

OnAdvancedCustomDrawItem 

OnAdvancedCustomDrawSubItem