TFont Property to control font of subclassed controls - delphi

Question

I have created a component descended from TPanel. In the constructor of the component I create several TButton components. I have created and surfaced a ButtonFont property of type TFont. This property controls the font of all the buttons on the component. Example:
TMyPanel = Class(TPanel)
private
FButtonFont : TFont;
FExampleButton : TButton;
procedure SetButtonFont(Value: TFont);
public
property ButtonFont: TFont read FButtonFont write SetButtonFont;
constructor Create (AOwner: TComponent); override;
end;
constructor TMyPanel.Create (AOwner: TComponent);
begin
FButtonFont := TFont.Create;
FExampleButton := TButton.Create(self);
FExampleButton.Parent := self;
.......
inherited;
end;
procedure TMyPanel.SetButtonFont(Value: TFont);
begin
FButtonFont.Assign(Value);
FExampleButton.Font := Value;
end;
The following will cause all subclassed buttons have their button font changed:
MyLabel.Font.Size := 22;
MyPanel.ButtonFont := label1.font;
I can see the SetButtonFont method is being called.
How can I get something like this to cause all subclassed buttons to change their font size:
MyPanel.ButtonFont.Size := 22;

Answer 1

Assign a handler to the font's OnChange event and update all the sub-controls' fonts in that handler:
constructor TMyPanel.Create(AOwner: TComponent);
begin
inherited;
FButtonFont := TFont.Create;
FButtonFont.OnChange := ButtonFontChanged; // <-- here
FExampleButton := TButton.Create(Self);
FExampleButton.Parent := Self;
...
end;
destructor TMyPanel.Destroy;
begin
...
FButtonFont.Free;
inherited;
end;
procedure TMyPanel.ButtonFontChanged(Sender: TObject);
begin
FExampleButton.Font := FButtonFont;
...
end;