Learn the mechanism of Tcomponent classes through the original code (1)

The best way to learn Delphi is to see Delphi's VCL original code love to see his mechanism. This article will look at his mechanism. {Tcomponent} constructor tComponent.create (Aowner: tComponent); begin fcomponentStyle: = [csinheritable ]; If aowner <> nil damponent (self);

Procedure Tcomponent.insertComponent (Acomponent: Tcomponent); Begin Acomponent.validateContainer (self); ValidateRename (Acomponent, '', Acomponent.fname); // See if there is a renameless object if there is an exception INSERT (Acomponent); / / Join Acomponent's reference to Acomponent (TRUE); if Csdesigning In ComponentState Then ACOMPONENT.SETDESIGNING (TRUE); NOTINTDESIGNING (TRUE); // Send yourself a notification message END;

procedure TComponent.ValidateRename (AComponent: TComponent; const CurName, NewName: string); begin if (AComponent <> nil) and not SameText (CurName, NewName) and (AComponent.Owner = Self) and (FindComponent (NewName) <> nil ) then raise EComponentError.CreateResFmt (@SDuplicateName, [NewName]); if (csDesigning in ComponentState) and (Owner <> nil) then Owner.ValidateRename (aComponent, CurName, NewName); // recursive call to check if there are duplicate of Component end;

Procedure Tcomponent.validateContainer (ACOMPONENT: TComponent); Begin Acomponent.ValidateInsert (Self); END;

Procedure Tcomponent.validateInsert (ACOMPONENT: TComponent); BeGund;

Procedure Tcomponent.insert (ACOMPONENT: TComponent); // We can see that the reference to his subcomponents is a Begin if fcomponents = nil damponents: = nil damponents: = tList.create; fcomponents.add (attomponent); Acomponent. FOWNER: = Self; // 加 主 主 主 主;;

destructor TComponent.Destroy; file: // can be seen that each component maintains a list of begin Destroying a FFREENOTIFILES; if FFreeNotifies <> nil then begin while Assigned (FFreeNotifies) and (FFreeNotifies.Count> 0) do TComponent (FFreeNotifies [FFreeNotifies .Count - 1]). Notification (Self, OpRemove); FreeAndnil (FFreenotifies); // When you destructure, call NOTIFICATION to the object referenced by you ffreenotifiles, tell them your own restructive event; destroyComponents; If FOWNER <> nil damponent (self); inherited destroy; end; procedure tcomponent.freenotification (ACOMPONENT: TCOMPONENT); // can confirm that ffreenotifiles is a list of this list to protect yourself to those objects notification begin if (Owner = nil) or (AComponent.Owner <> Owner) then begin // Never acquire a reference to a component that is being deleted assert (not (csDestroying in (ComponentState AComponent.ComponentState)));. if NOT ASSIGNED (FFreenotifies) THEN FFREENOTIFIES: = TList.create; if ffreenotifies.indexof (ACOMPONENT) <0 The begin ffreenotifies.add (Acomponent); Acomponent.Freenotification (S END; End; End; Include (fcomponentState, csfreenotification);