Case和if使用节选代码（摘自Delphi安装目录代码）

procedure TSpinButton.KeyDown(var Key: Word; Shift: TShiftState);
begin
  case Key of
    VK_UP:
      begin
        SetFocusBtn (FUpButton);
        FUpButton.Click;
      end;
    VK_DOWN:
      begin
        SetFocusBtn (FDownButton);
        FDownButton.Click;
      end;
    VK_SPACE:
      FFocusedButton.Click;
  end;
end;

procedure TSpinButton.BtnMouseDown (Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  if Button = mbLeft then
  begin
    SetFocusBtn (TTimerSpeedButton (Sender));
    if (FFocusControl <> nil) and FFocusControl.TabStop and
        FFocusControl.CanFocus and (GetFocus <> FFocusControl.Handle) then
      FFocusControl.SetFocus
    else if TabStop and (GetFocus <> Handle) and CanFocus then
      SetFocus;
  end;
end;