Lazarus

Programming => LCL => Topic started by: Pe3s on October 24, 2021, 08:23:47 pm

Title: Mouse Events for all components
Post by: Pe3s on October 24, 2021, 08:23:47 pm

Hello, how can I implement events for all TPanel components, I mean onMouseEnter, onMouseLeave events
I wrote a loop but I have a problem with the MouseEnter and MouseLeave events

Code: Pascal  [Select][+][-]

1. var
2.   Form1: TForm1;
3.  
4.   const
5.   _clMouseEntered = clRed;
6.   _clMouseLeaved = clHighlight;
7.  
8. implementation
9.  
10. {$R *.frm}
11.  
12. { TForm1 }
13.  
14. procedure TForm1.FormCreate(Sender: TObject);
15. var
16.   i: Integer;
17. begin
18.    for i := 0 to ComponentCount-1 do
19.     if Components[i] is TPanel then with TPanel(Components[i]) do
20.     begin
21.       OnMouseEnter :=
22.       OnMouseLeave :=
23.     end;
24. end;    

Title: Re: Mouse Events for all components
Post by: Handoko on October 24, 2021, 08:54:51 pm

Hello Pe3s,
Welcome to the forum.

It should be something like this:

Code: Pascal  [Select][+][-]

1.   { TForm1 }
2.  
3.   TForm1 = class(TForm)
4.      .
5.      .
6.   private
7.     procedure MyPanelMouseEnter(Sender: TObject);
8.     procedure MyPanelMouseLeave(Sender: TObject);
9.      .
10.      .
11.   end;
12.      .
13.      .
14.  
15. implementation
16.  
17. {$R *.lfm}
18.  
19. { TForm1 }
20.  
21. procedure TForm1.FormCreate(Sender: TObject);
22. var
23.   i: Integer;
24. begin
25.    for i := 0 to ComponentCount-1 do
26.     if Components[i] is TPanel then with TPanel(Components[i]) do
27.     begin
28.       OnMouseEnter := @MyPanelMouseEnter;
29.       OnMouseLeave := @MyPanelMouseLeave;
30.     end;
31. end;

Title: Re: Mouse Events for all components
Post by: Pe3s on October 25, 2021, 05:39:02 pm

I tried to change the color of the tPanel component, but it does not work

Code: Pascal  [Select][+][-]

1. unit Unit1;
2.  
3. {$mode objfpc}{$H+}
4.  
5. interface
6.  
7. uses
8.   Classes, SysUtils, Forms, Controls, Graphics, Dialogs, ExtCtrls;
9.  
10. type
11.  
12.   { TForm1 }
13.  
14.   TForm1 = class(TForm)
15.     Panel1: TPanel;
16.     Panel2: TPanel;
17.     Panel3: TPanel;
18.     Panel4: TPanel;
19.     procedure FormCreate(Sender: TObject);
20.   private
21.     procedure MyPanelMouseEnter(Sender: TObject);
22.     procedure MyPanelMouseLeave(Sender: TObject);
23.   public
24.  
25.   end;
26.  
27. var
28.   Form1: TForm1;
29.  
30. implementation
31.  
32. {$R *.lfm}
33.  
34. { TForm1 }
35.  
36.  
37. procedure TForm1.FormCreate(Sender: TObject);
38. var
39.   i: Integer;
40. begin
41.    for i := 0 to ComponentCount-1 do
42.     if Components[i] is TPanel then with TPanel(Components[i]) do
43.     begin
44.       OnMouseEnter:=@MyPanelMouseEnter;
45.       OnMouseLeave:=@MyPanelMouseLeave;
46.     end;
47. end;
48.  
49. procedure TForm1.MyPanelMouseEnter(Sender: TObject);
50. begin
51.  
52. end;
53.  
54. procedure TForm1.MyPanelMouseLeave(Sender: TObject);
55. begin
56.  
57. end;
58.  
59. end.              

I have a problem with completing the procedures

procedure TForm1.MyPanelMouseEnter(Sender: TObject);
begin
     Color:= clRed;
end;

procedure TForm1.MyPanelMouseLeave(Sender: TObject);
begin
    Color:= clLime;

end;   

Title: Re: Mouse Events for all components
Post by: devEric69 on October 25, 2021, 05:52:05 pm

Reusing the transtyping \ typecasting (like jamie showed), you should call TPanel(Sender).Color:= clRed; in your @MyPanelMouseEnter and @MyPanelMouseLeave commun events shared between the panels.

Title: Re: Mouse Events for all components
Post by: Pe3s on October 25, 2021, 05:57:03 pm

Quote from: devEric69 on October 25, 2021, 05:52:05 pm

Reusing the transtyping \ typecasting (like @jamie showed), you should call TPanel(Sender).Color:= clRed; in your @MyPanelMouseEnter and @MyPanelMouseLeave commun events shared between the panels.

Thank you :)

Title: Re: Mouse Events for all components
Post by: Pe3s on October 25, 2021, 06:01:54 pm

problem solved  :)

Title: Re: Mouse Events for all components
Post by: ASerge on October 25, 2021, 08:53:01 pm

TForm has an enumerator for components. In my opinion the following code looks better:

Code: Pascal  [Select][+][-]

1. procedure TForm1.FormCreate(Sender: TObject);
2. var
3.   C: TComponent;
4. begin
5.   for C in Self do
6.     if C is TPanel then
7.     begin
8.       TPanel(C).OnMouseEnter := @MyPanelMouseEnter;
9.       TPanel(C).OnMouseLeave := @MyPanelMouseLeave;
10.     end;
11. end;

Title: Re: Mouse Events for all components
Post by: Pe3s on October 26, 2021, 04:53:49 pm

Thank you  :)