[SOLVED]Send an Element to function ?!?

[majid.ebru]

Hi
.
i read some post but i can not find answer!!
.
how can i send an element(like a button or an editbox) to a function ?!?!?
.
how can i send an element with pointer to function and use it in the function??
.
Thank you

[sky_khan]

as any other argument

Code: Pascal  [Select][+][-]

1. type
2.   TLabelFunc = function (aLabel:TLabel):string of object;
3.  
4. procedure TForm1.Button1Click(Sender: TObject);
5. begin
6.   ShowTime(Label1);
7. end;
8.  
9. procedure TForm1.Button2Click(Sender: TObject);
10. begin
11.   ShowTimeBy(@ShowTime);
12. end;
13.  
14. procedure TForm1.ShowTimeBy(aLabelFunc: TLabelFunc);
15. begin
16.   aLabelFunc(Label1);
17. end;
18.  
19. function TForm1.ShowTime(aLabel: TLabel): string;
20. begin
21.   Result:=FormatDateTime('MM DD YYYY hh:nn',Now);
22.   aLabel.Caption:=Result;
23. end;
24.  

[majid.ebru]

i confused ?!?!?!?!??!
 
.
can you say an eyse sample
.
just send an element to function and change it
.
(for example send a button to function(procedure) and change name button)

[Thaddy]

Well, then you have to explain better what you want, because SkyKhan's example is pretty obvious.
(Apart from missing two const modifiers in the method headers, but that does not affect functionality.)

[Handoko]

Try my example, you can download the ready to run code.

Code: Pascal  [Select][+][-]

1. unit Unit1;
2.  
3. {$mode objfpc}{$H+}
4.  
5. interface
6.  
7. uses
8.   Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, StdCtrls;
9.  
10. type
11.  
12.   { TForm1 }
13.  
14.   TForm1 = class(TForm)
15.     Button1: TButton;
16.     Button2: TButton;
17.     Button3: TButton;
18.     Button4: TButton;
19.     Memo1: TMemo;
20.     procedure Button1Click(Sender: TObject);
21.     procedure Button2Click(Sender: TObject);
22.     procedure Button3Click(Sender: TObject);
23.     procedure Button4Click(Sender: TObject);
24.   end;
25.  
26. var
27.   Form1: TForm1;
28.  
29. implementation
30.  
31. {$R *.lfm}
32.  
33. procedure ChangeButton(Sender: TObject);
34. var
35.   NewCaption: string;
36. begin
37.   if not(Sender is TButton) then Exit;
38.  
39.   NewCaption := 'Btn' + IntToStr(Random(999));
40.   Form1.Memo1.Text := 'You have clicked ' + TButton(Sender).Caption + '. ' +
41.                       'And now it is changed to ' + NewCaption + '.';
42.  
43.   TButton(Sender).Caption := NewCaption;
44. end;
45.  
46. { TForm1 }
47.  
48. procedure TForm1.Button1Click(Sender: TObject);
49. begin
50.   ChangeButton(Sender);
51. end;
52.  
53. procedure TForm1.Button2Click(Sender: TObject);
54. begin
55.   ChangeButton(Sender);
56. end;
57.  
58. procedure TForm1.Button3Click(Sender: TObject);
59. begin
60.   ChangeButton(Sender);
61. end;
62.  
63. procedure TForm1.Button4Click(Sender: TObject);
64. begin
65.   ChangeButton(Sender);
66. end;
67.  
68. end.

[majid.ebru]

Thank you.
.
but i should send many elements to function.
.
in your sample , you just send one element to function.
.
i should send two button and one editbox and one stringgrid to function
.
.
[i have 4 panels and in each panel has two button and one editbox and one stringgrid. i don't want to write code for eath panel and i want to write one code for each panel]
.
.
thank you

[sky_khan]

In Turkish we say "Armut piş ağzıma düş". I think it can be translated like "Let a pear is ripened and fall into my mouth".
I dont know any similar idiom in English. Do you ?

[Handoko]

@SkyKhan

Calm down friend, he's just a newbie.

@majid.ebru

In my code I use TObject and pass Sender as the variable, you can change it to the things you want, like:

Code: Pascal  [Select][+][-]

1. procedure ChangeButton(Button1, Button2: TButton; Edit: TEdit; Grid: TStringGrid);

You just have to make sure the unit that has that function, has StdCtrls and Grids in the unit clause.

[bylaardt]

another way you can change several controls at the same time:

Code: Pascal  [Select][+][-]

1. procedure DisableControls(MyControls:Array of TControl);
2. var
3.   h:Integer;
4. begin
5.   for h:=Low(MyControls) to High(MyControls) do
6.     TControl(MyControls[h]).Enabled:=false;
7. end;
8.        

And calling this procedure so:

Code: Pascal  [Select][+][-]

1.  DisableControls([button2,button3,button4,Label1,label2,label3,StringGrid1,Edit1]);

[Handoko]

+1 bylaardt

Using open array to pass parameter and accessing it using low and high.
It is a nice trick.
 

[Handoko]

(for example send a button to function(procedure) and change name button)

Maybe I'm wrong, but as far as I know, we cannot change button's name runtime.

[majid.ebru]

Hi again
.
i think that i cann't explain my problem.
.
i have 2 button in each panel and each 2 button dose same code.
.
i want to use pointer and use pointer in function.
.
in the function caption of buttons and text of editbox must change?!?!
.
thank you for answer.

[howardpc]

Maybe I'm wrong, but as far as I know, we cannot change button's name runtime.

You can change a component's name at runtime. See attached example.

[Handoko]

Cool. But I failed to open your example.
I'm using Lazarus 1.6.4 Ubuntu Mate 64-bit.

In what cases we need to change the component's name runtime? I don't think we will need it.

[Handoko]

@majid.ebru

Not really sure what you want to do. You can download my example, perhaps that is what you want.

Code: Pascal  [Select][+][-]

1. unit Unit1;
2.  
3. {$mode objfpc}{$H+}
4.  
5. interface
6.  
7. uses
8.   Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, StdCtrls,
9.   ExtCtrls;
10.  
11. type
12.  
13.   { TForm1 }
14.  
15.   TForm1 = class(TForm)
16.     Button1: TButton;
17.     Button2: TButton;
18.     Button3: TButton;
19.     Button4: TButton;
20.     Button5: TButton;
21.     Button6: TButton;
22.     Button7: TButton;
23.     Button8: TButton;
24.     Edit1: TEdit;
25.     Edit2: TEdit;
26.     Edit3: TEdit;
27.     Edit4: TEdit;
28.     Label1: TLabel;
29.     Panel1: TPanel;
30.     Panel2: TPanel;
31.     Panel3: TPanel;
32.     Panel4: TPanel;
33.     procedure Panel1MouseEnter(Sender: TObject);
34.     procedure Panel1MouseLeave(Sender: TObject);
35.     procedure Panel2MouseEnter(Sender: TObject);
36.     procedure Panel2MouseLeave(Sender: TObject);
37.     procedure Panel3MouseEnter(Sender: TObject);
38.     procedure Panel3MouseLeave(Sender: TObject);
39.     procedure Panel4MouseEnter(Sender: TObject);
40.     procedure Panel4MouseLeave(Sender: TObject);
41.   end;
42.  
43. var
44.   Form1: TForm1;
45.  
46. implementation
47.  
48. {$R *.lfm}
49.  
50. procedure DisableControls(Btn1, Btn2: TButton; Edit: TEdit);
51. begin
52.   Btn1.Caption := '-disabled-';
53.   Btn2.Caption := '-disabled-';
54.   Btn1.Enabled := False;
55.   Btn2.Enabled := False;
56.   Edit.Enabled := False;
57. end;
58.  
59. procedure EnableControls(Btn1, Btn2: TButton; Edit: TEdit);
60. begin
61.   Btn1.Caption := 'New';
62.   Btn2.Caption := 'Save';
63.   Btn1.Enabled := True;
64.   Btn2.Enabled := True;
65.   Edit.Enabled := True;
66. end;
67.  
68. { TForm1 }
69.  
70. procedure TForm1.Panel1MouseEnter(Sender: TObject);
71. begin
72.   EnableControls(Button1, Button2, Edit1);
73. end;
74.  
75. procedure TForm1.Panel1MouseLeave(Sender: TObject);
76. begin
77.   DisableControls(Button1, Button2, Edit1);
78. end;
79.  
80. procedure TForm1.Panel2MouseEnter(Sender: TObject);
81. begin
82.   EnableControls(Button3, Button4, Edit2);
83. end;
84.  
85. procedure TForm1.Panel2MouseLeave(Sender: TObject);
86. begin
87.   DisableControls(Button3, Button4, Edit1);
88. end;
89.  
90. procedure TForm1.Panel3MouseEnter(Sender: TObject);
91. begin
92.   EnableControls(Button5, Button6, Edit3);
93. end;
94.  
95. procedure TForm1.Panel3MouseLeave(Sender: TObject);
96. begin
97.   DisableControls(Button5, Button6, Edit3);
98. end;
99.  
100. procedure TForm1.Panel4MouseEnter(Sender: TObject);
101. begin
102.   EnableControls(Button7, Button8, Edit4);
103. end;
104.  
105. procedure TForm1.Panel4MouseLeave(Sender: TObject);
106. begin
107.   DisableControls(Button7, Button8, Edit4);
108. end;
109.  
110. end.