Choose whether to close the program

[xinyiman]

Iotated that when I close the window, I asked if I really want to close the program! How do I do if I say no to not close the program?

Thank you

[theo]

TForm has event OnCloseQuery.
You can set parameter "CanClose" to false.

[xinyiman]

sample example

[M[a]nny]

For completeness:
(add LclType unit)

Code: [Select]

if Application.MessageBox('Are you sure you want to quit?', 'Question', MB_YesNo + MB_IconQuestion) = IdYes then Application.Terminate else CanClose := False;

[xinyiman]

Error example

Hint: Start of reading config file C:\lazarus\fpc\2.4.0\bin\i386-win32\fpc.cfg
Hint: End of reading config file C:\lazarus\fpc\2.4.0\bin\i386-win32\fpc.cfg
Free Pascal Compiler version 2.4.0 [2010/07/19] for i386
Copyright (c) 1993-2009 by Florian Klaempfl
Target OS: Win32 for i386
Compiling project1.lpr
Compiling unit1.pas
unit1.pas(29,24) Hint: Parameter "Sender" not used
unit1.pas(28,27) Hint: Parameter "Sender" not used
unit1.pas(26,30) Hint: Parameter "Sender" not used
unit1.pas(88,87) Error: Identifier not found "MB_YesNo"
unit1.pas(88,104) Error: Identifier not found "MB_IconQuestion"
unit1.pas(88,114) Error: Identifier not found "IdYes"
unit1.pas(91,17) Error: Identifier not found "CanClose"
unit1.pas(196) Fatal: There were 4 errors compiling module, stopping

[M[a]nny]

Read carefuly... you have to add unit LclType to uses.

Code: [Select]

uses
  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, LclType; 

[xinyiman]

Error CanClose 

Hint: Start of reading config file C:\lazarus\fpc\2.4.0\bin\i386-win32\fpc.cfg
Hint: End of reading config file C:\lazarus\fpc\2.4.0\bin\i386-win32\fpc.cfg
Free Pascal Compiler version 2.4.0 [2010/07/19] for i386
Copyright (c) 1993-2009 by Florian Klaempfl
Target OS: Win32 for i386
Compiling project1.lpr
Compiling unit1.pas
unit1.pas(29,24) Hint: Parameter "Sender" not used
unit1.pas(28,27) Hint: Parameter "Sender" not used
unit1.pas(26,30) Hint: Parameter "Sender" not used
unit1.pas(91,17) Error: Identifier not found "CanClose"
unit1.pas(201) Fatal: There were 1 errors compiling module, stopping

[xinyiman]

procedure TForm1.FormClose(Sender: TObject; var CloseAction: TCloseAction);
begin
     if Application.MessageBox('Are you sure you want to quit?', 'Question', MB_YesNo + MB_IconQuestion) = IdYes then
        Application.Terminate
     else
       CanClose:=FALSE;
end;

Error!

[xinyiman]

resolved


procedure TForm1.FormCloseQuery(Sender: TObject; var CanClose: boolean);
begin
     if Application.MessageBox('Are you sure you want to quit?', 'Question', MB_YesNo + MB_IconQuestion) = IdYes then
        Application.Terminate
     else
        CanClose := FALSE;
end;       

[M[a]nny]

Yes, you should place that snippet of code to CloseQuery event of the TForm because of using CanClose.