Delphi中给活动控件画上矩形边框

  {private

    procedure DrawFocusRectangle(sender: TObject);

  public

    { Public declarations }

  end;}



var

  Form1: TForm1;

  FocusRectangle: TShape;



implementation



{$R *.dfm}



//窗体创建事件中加如下代码
procedure TForm1.FormCreate(Sender: TObject);

begin

  FocusRectangle := TShape.Create(Self);

  FocusRectangle.Shape := stRectangle;

  FocusRectangle.Visible := False;

  FocusRectangle.Brush.Style := bsClear;

  FocusRectangle.Pen.Style := psDot;

  FocusRectangle.Pen.Color := clRed;

  FocusRectangle.Pen.Width := 1;

{在Screen的OnActiveControlChange事件中处理}
  Screen.OnActiveControlChange := DrawFocusRectangle;

end;



procedure TForm1.DrawFocusRectangle;

begin

  with FocusRectangle do

  begin

    Parent := Screen.ActiveControl.Parent;

    Top := Screen.ActiveControl.Top -2 ;

    Height := Screen.ActiveControl.Height + 4;

    Left := Screen.ActiveControl.Left - 2;

    Width := Screen.ActiveControl.Width + 4;

    Visible := True;

  end;

end;



procedure TForm1.FormDestroy(Sender: TObject);

begin

  Screen.OnActiveControlChange := nil;

  FocusRectangle.Free;

end;