Dateiliste

As mentioned earlier, the scan could take a very long time, maybe even several hours. It is unacceptable not to provide an option to cancelling the process.

The Cancel button is actually there, stuck on the installation wizard. It's just not visible while the progress page works.

To get the button back, it needs to be made visible:

WizardForm.CancelButton.Visible := TRUE;

Once the Cancel button is visible it automatically gets its function back. Of course, it can't interrupt the directory reading function while files are read in and being processed. When Cancel is clicked, the directory scan happily carries on, and as soon as it is finished Inno Setup asks if the installation is to be aborted.

This still is not how it should be. The scan should be stopped immediately, or at least as quickly as possible.

Inno Setup's script engine provides an event function for the Cancel button: CancelButtonClick ().

With a simple message box identical to the 'Exit Setup' confirmation message I tricked the user in believing that they see Inno Setup's original confirmation:

procedure CancelButtonClick (CurPageID: Integer; var Cancel, Confirm: Boolean);
// No confirmation message, because we roll our own.
// The base idea has been nicked from
// http://www.vincenzo.net/isxkb/index.php?title=No_%27Exit_Setup%27_message .
// The only difference to Inno Setup's 'Exit Setup' message box is its title,
// but that's only a minor cosmetic glitch.
begin
 Confirm := FALSE;
 if (MsgBox (SetupMessage (msgExitSetupMessage),
 mbConfirmation, MB_YESNO) = IDYES) then
 begin
 bExitSetup := TRUE;
 end;
end;
 

The difference between this 'Exit Setup' confirmation box and Inno Setup's own can be seen in the window title.

The original confirmation message box is called 'Exit Setup' (image on the top) while mine contains the title of the setup (bottom image), which is 'Setup' by default. Although this is a fairly good working solution already, I was not happy with this difference.

Since Inno Setup uses the Windows API MessageBox (), I was sure it can be used too to correct the window title. I found the declaration for Pascal script on the ISXKB under MessageBox () and nicked it from there:

[Code]
function MessageBox (hWnd: Integer; lpText, lpCaption: String; uType: Cardinal): Integer; external 'MessageBoxA@user32.dll stdcall';

Pascal seems a bit picky when it comes to types, hence I didn't want to bother with all those required conversions and looked up the parameter constants in the file WinUser.h from the Windows SDK instead. Here's the relevant excerpt from that file:

/*
 * MessageBox() Flags
 */
#define MB_OK                       0x00000000L
#define MB_OKCANCEL                 0x00000001L
#define MB_ABORTRETRYIGNORE         0x00000002L
#define MB_YESNOCANCEL              0x00000003L
#define MB_YESNO                    0x00000004L
#define MB_RETRYCANCEL              0x00000005L
#if(WINVER >= 0x0500)
#define MB_CANCELTRYCONTINUE        0x00000006L
#endif /* WINVER >= 0x0500 */
 
 
#define MB_ICONHAND                 0x00000010L
#define MB_ICONQUESTION             0x00000020L
#define MB_ICONEXCLAMATION          0x00000030L
#define MB_ICONASTERISK             0x00000040L
 
#if(WINVER >= 0x0400)
#define MB_USERICON                 0x00000080L
#define MB_ICONWARNING              MB_ICONEXCLAMATION
#define MB_ICONERROR                MB_ICONHAND
#endif /* WINVER >= 0x0400 */
 
#define MB_ICONINFORMATION          MB_ICONASTERISK
#define MB_ICONSTOP                 MB_ICONHAND
 
#define MB_DEFBUTTON1               0x00000000L
#define MB_DEFBUTTON2               0x00000100L
#define MB_DEFBUTTON3               0x00000200L
#if(WINVER >= 0x0400)
#define MB_DEFBUTTON4               0x00000300L
#endif /* WINVER >= 0x0400 */
 
#define MB_APPLMODAL                0x00000000L
#define MB_SYSTEMMODAL              0x00001000L
#define MB_TASKMODAL                0x00002000L
#if(WINVER >= 0x0400)
#define MB_HELP                     0x00004000L // Help Button
#endif /* WINVER >= 0x0400 */
 
#define MB_NOFOCUS                  0x00008000L
#define MB_SETFOREGROUND            0x00010000L
#define MB_DEFAULT_DESKTOP_ONLY     0x00020000L
 
#if(WINVER >= 0x0400)
#define MB_TOPMOST                  0x00040000L
#define MB_RIGHT                    0x00080000L
#define MB_RTLREADING               0x00100000L
 
 
#endif /* WINVER >= 0x0400 */
 

I used the values directly and changed the function accordingly:

procedure CancelButtonClick (CurPageID: Integer; var Cancel, Confirm: Boolean);
begin
 Confirm := FALSE;
 if (MessageBox (0, SetupMessage (msgExitSetupMessage),
 SetupMessage (msgExitSetupTitle), 4 + 32) = 6) then
 begin
 bExitSetup := TRUE;
 end;
end;
 

The outcome is an example Inno Setup script that scans the entire C: drive. If the user gets bored of watching the scan they can press the Cancel button and terminate the installer.