A Dialog derived from CDialog returns -1 after DoModal (MFC/C++)

Question

I have created a Dialog which it's derived from CDialog (MFC does this automatically), but I had to override the OnInitDialog method to make initialization of a ComboBox:

BOOL CLogin::OnInitDialog()
{
 CDialog::OnInitDialog();

 InitCommonControls();

 if ( FillInCombo() != 0 )
  //erro ao tentar ler leitoras
  return TRUE;

 return TRUE;
}

The method FillInCombo calls a PCSC class to fill this combo with all available smart card readers.

However, while debugging a strange behavior takes place. While attempting to select an item on the combo, it closes automatically (it actually generates an OnClose event) and DoModal returns -1.

Then, next, the application is never again loaded correctly unless I clean the solutions and build it again.

 CLogin SmartNetData;
 int ret = SmartNetData.DoModal();
 switch ( ret )
 {
    case IDOK:
    break;
    case -1: 
    // strange error
    OnOK();
    return TRUE;
    case IDABORT:
    case IDCANCEL:
    OnOK();
    return TRUE;
 };

Thanks for any possible help on this.

LATER EDIT: I realized the problem arises because of the combobox. I am not sure why. I replaced it by a ListBox and I am not getting troubles.

Not direclty, I have a button to fire the extraction of the item in the combo after the user selected the item. — zlogdan, Jan 11 '11 at 18:52

score 2 · Accepted Answer · answered Jan 12 '11 at 01:29

2

I suspect some thing goes wrong in your OnInitDialog().

I suggest you to go for debug steps:
a) remove InitCommonControls() in OnInitDialog()
b) remove FillInCombo() in OnInitDialog()
c) remove InitCommonControls() and FillInCombo() in OnInitDialog()

After removing one by one, check with the DoModal returns value.

answered Jan 12 '11 at 01:29

wengseng

1,330
1
14
27

Thanks for the help! I removed the FillinCombo function. I gave a lot of thought on this ( I read your answer yesterday night at home) and it looked like you were right, as this function calls a PCSC DLL and uses a std::vector but man I removed it and it still persists. I have removed the InitCommonControls function as unwind explained that it was not necessary at all. The method InitCommonControlsEx is alread called in the main class created by the MFC Wizard. – zlogdan Jan 12 '11 at 11:09
It is something within the code that VS 2005 generates for the combobox. Or something I missed . – zlogdan Jan 13 '11 at 14:47

score 0 · Answer 2 · answered Jan 11 '11 at 16:24

0

I think you're doing InitCommonControls() in the wrong place. This should be done once in your program. It initializes the common controls library. Not the controls on your dialog themselves.

I typically put this in the app's startup routine, before bringing any windows up.

answered Jan 11 '11 at 16:24

John Dibling

99,718
31
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324

Thanks for the help" I removed it from code, but the problem still persists. – zlogdan Jan 11 '11 at 18:09

A Dialog derived from CDialog returns -1 after DoModal (MFC/C++)

2 Answers2