scrollbox mouse wheel delphi

Question

How to add OnMouseWheel to the same form for two scrollboxes? I applied the method to ScrollBox1 but I did not know how to add the method to ScrollBox2

procedure TForm3.FormMouseWheel(Sender: TObject; Shift: TShiftState;
  WheelDelta: Integer; MousePos: TPoint; var Handled: Boolean);
var
  LTopLeft, LTopRight, LBottomLeft, LBottomRight: SmallInt;
  LPoint: TPoint;
begin
   inherited;
  LPoint := ScrollBox1.ClientToScreen(Point(0,0));

  LTopLeft := LPoint.X;
  LTopRight := LTopLeft + ScrollBox1.Width;

  LBottomLeft := LPoint.Y;
  LBottomRight := LBottomLeft + ScrollBox1.Width;


  if (MousePos.X >= LTopLeft) and
    (MousePos.X <= LTopRight) and
    (MousePos.Y >= LBottomLeft)and
    (MousePos.Y <= LBottomRight) then
  begin
    ScrollBox1.VertScrollBar.Position :=
    ScrollBox1.VertScrollBar.Position - WheelDelta;

    Handled := True;
  end;
end;

Answer 1

Assign the same handler to both ScrollBox components, not to the Form, and then use the Sender parameter to know which component is calling the handler.

procedure TForm3.ScrollBoxMouseWheel(Sender: TObject;
  Shift: TShiftState; WheelDelta: Integer; MousePos: TPoint;
  var Handled: Boolean);
var
  LTopLeft, LTopRight, LBottomLeft, LBottomRight: SmallInt;
  LPoint: TPoint;
  ScrollBox: TScrollBox;
begin
  ScrollBox := TScrollBox(Sender);
  LPoint := ScrollBox.ClientToScreen(Point(0,0));
  LTopLeft := LPoint.X;
  LTopRight := LTopLeft + ScrollBox.ClientWidth;
  LBottomLeft := LPoint.Y;
  LBottomRight := LBottomLeft + ScrollBox.ClientWidth;
  if (MousePos.X >= LTopLeft) and
    (MousePos.X <= LTopRight) and
    (MousePos.Y >= LBottomLeft) and
    (MousePos.Y <= LBottomRight) then
  begin
    ScrollBox.VertScrollBar.Position := ScrollBox.VertScrollBar.Position - WheelDelta;
    Handled := True;
  end;
end;