void __fastcall Destroying(void);
Indicates that the component and its owned components are about to be destroyed.
Destroying sets the csDestroying flag in the ComponentState property. It then calls the Destroying method for each owned component so that its csDestroying flag is also set. If csDestroying is already set, Destroying does nothing.
It is not necessary to call Destroying directly. Destroying is automatically called when the component is destroyed.