Ask user to save file before exiting.

I dont have my Petzold book handy and I am having difficulty with asking the user to save the file when File|Exit is selected and the file has changes that are unsaved.

When I select the save dialog directly from the menu it works flawlessly, but I can't get it to ask the user to save the file, when a user selects 'exit' from the menu or the 'close' button.

Dialog box asks: "Save current changes?"
1. When I press: 'no' it closes the application as it should.
2. When I press: 'cancel' the dialog box is dismissed and the application continues as it should!
3. The trouble begins when I press: 'yes' the dialog box is destroyed and the application contiues running without exiting or running the IDM_FILE_SAVE.

What have I done incorrectly?



I am guessing my error is somewhere in the following code:

Code:

---

case IDM_FILE_EXIT:
        SendMessage (hwnd, WM_CLOSE, 0, 0);
        return 0 ;

case WM_DESTROY:  // This case actually terminates the process.
        PostQuitMessage (0);
        return 0;

case WM_CLOSE :
        if ( !bFileNeedsSaved || IDCANCEL != AskAboutSave())
                DestroyWindow(hwnd);
        return 0;

case WM_QUERYENDSESSION :
        if ( !bFileNeedsSaved || IDCANCEL != AskAboutSave())
                return 1;
        return 0;


int AskAboutSave ()
{
    int  iReturn ;
   
        iReturn = MessageBox (hwnd, "Save current changes?", szAppName,
                          MB_YESNOCANCEL | MB_ICONQUESTION) ;
   
    if (iReturn == IDYES)
          if (!SendMessage (hwnd, WM_COMMAND, IDM_FILE_SAVE, 0))
              iReturn = IDCANCEL ;

        // SendMessage(hwnd, WM_COMMAND, IDM_FILE_SAVE, 0);

         
    return iReturn ;
}

case IDM_FILE_SAVE:
        strcat(PathAndFilename, pDefaultSaveLocation);
        if(GetSaveFileName(&ofn))
        {
                pPathAndFilename = ofn.lpstrFile;
                if((fp = fopen (pPathAndFilename, "w"))==NULL)        //a+ append/create and or overwrite.
                {
                        MessageBox (hwnd, TEXT ("Cannot save file!"),
                                szAppName, MB_ICONEXCLAMATION | MB_OK);
                        exit(1);
                }
                // Write the file!
                WriteData ();
                fclose(fp);
                bFileNeedsSaved = false;
                //strip everything but filename from pPathAndFilename and store it into szFileName.  See
                char Temp[MAX_PATH];
                char* pTemp = &Temp[0];
                pTemp = strrchr(pPathAndFilename, '\\');
                pTemp++;
                char * szFileName = pTemp;
        }
        MessageBeep (0) ;
        return 0 ;

---

What's happening is you're sending a message that doesn't get the time to be processed before your window gets killed. What would be a wiser alternative would be to shell out IDM_FILE_SAVE and put it in a function, then call that function from IDM_FILE_SAVE, and also from the message box place.

This way, you're ensured to save the file immediately instead of hoping windows processes your message before killing your program.

I think this could be the problem

SendMessage (hwnd, WM_COMMAND, IDM_FILE_SAVE, 0)

Is the hwnd correct?

try....

(include Windows.h)
//in MAKEWPARAM send 1 for control, 0 for menu item
// hwnd is for the parents callback

SendMessage (hwnd, MAKEWPARAM( 1, IDM_FILE_SAVE), (LPARAM) GetDlgItem( hwnd, IDM_FILE_SAVE) );

Thanks for the input jverkoey and novacain, I'll give both your suggestions a whirl! :)

...
This is what I ended up doing to get it to work! Hopefully it will help someone else out:

Code:

---

int AskAboutSave (HWND hwnd)
{
    int  iReturn ;
    iReturn = MessageBox (NULL, "Save current changes?", szAppName,
                          MB_YESNOCANCEL | MB_ICONQUESTION) ;
    if (iReturn == IDYES)
                SendMessage(hwnd, WM_COMMAND, IDM_FILE_SAVE, 0);
    return iReturn ;
}

---