Get text from CComboBox

10,188

Solution 1

You need to call GetWindowText before the dialog is destroyed. A good place to do that would be in the DoDataExchange member function of the dialog.

Edit: You can also get an error if the CComboBox object hasn't been attached to the actual window. This also typically occurs in DoDataExchange.

Solution 2

You can get the combo box text inline with the following code:

CString cStr;
CWnd* Pfield = GetDlgItem(MY_COMBOBOX_ID);
Pfield->GetWindowText(cStr);
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JHowzer
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JHowzer

Updated on June 08, 2022

Comments

  • JHowzer
    JHowzer almost 2 years

    I have a CDialog (myDialogBox) that has a CComboBox member (myComboBox). My goal is to get the user-typed text (preferably as a CString) from the edit portion of a dropdown style CComboBox. But, I cannot seem to get it to work.

    I've tried using myComboBox.GetWindowText(myString). But whenever I run it in debug mode, my code breaks at ASSERT(::IsWindow(m_hWnd)) within the CWnd::GetWindowText() function.

    I've also tried myDialogBox.GetDlgItemText(MY_COMBOBOX_ID, myString), which breaks down in a similar way.

    Additionally, I've tried:

        COMBOBOXINFO info;
        memset(&info,0,sizeof(info));
        myComboBox.GetComboBoxInfo(&info);
        LPTSTR str = new TCHAR[::GetWindowTextLength(info.hwndItem)];
        ::GetWindowText(info.hwndItem,str,::GetWindowTextLength(info.hwndItem));
    

    But, it doesn't seem to be populating my info variable correctly.

    Could someone point me in the right direction, please? What am I doing wrong? Any suggestions?

    EDIT: Just in case it might help understand my ultimate goal, I am trying to have a combo-box where that can help a user pic and choose from a listing of strings. Nonetheless, if he/she does not want any on the dropdown-list, he can come up with his own string. I'd like a way to receive his user-typed string.

  • JHowzer
    JHowzer over 11 years
    What's odd is that it's happening even when I haven't destroyed the dialog box. To check, I made a function that occurs OnEditChangeMyComboBox, which only does the following: UpdatesData(TRUE), then it tries to get the text. It doesn't destroy the dialog or anything.
  • JHowzer
    JHowzer over 11 years
    As far as DoDataExchange, I have CDialog::DoDataExchange(pDX); DDX_Control(pDX, MY_COMBOBOX_ID, myComboBox);. Is that sufficient to attach it to the dialog?
  • Mark Ransom
    Mark Ransom over 11 years
    @JHowzer, yes that should be sufficient. However the error you're getting is that there's no window attached to the object. I'm out of ideas on how that could occur.
  • acraig5075
    acraig5075 over 11 years
    Make sure the ID property for the control in the Dialog Editor is still in fact MY_COMBOBOX_ID and that it hasn't accidently been changed. If the ID is now different, then the solution will still build but the combobox won't have a valid window handle.
  • JHowzer
    JHowzer over 11 years
    I realized I was missing a CString variable tied to the combo-box. This also required adding DDX_CBString(pDX, MY_COMBO_ID, myComboString); to DoDataExchange. After that, I UpdateData(TRUE); when selecting or editchange events occur. Thank you both for your help.
  • Mark Ransom
    Mark Ransom over 11 years
    @JHowzer it's good that you got it to work. I wouldn't have expected your solution to be any more successful than the others based on the error you were getting.