QFileDialog setNameFilter can be fooled



  • Let's say I want a QFileDialog that can open only specific extensions. I do this:

    m_dialog.setFileMode(QFileDialog::ExistingFile);
    m_dialog.setOption(QFileDialog::ReadOnly, true);
    
    m_dialog.setNameFilter(tr("Models (*.jpg)"));
    
    m_dialog.setOption(QFileDialog::ReadOnly, true);
    m_dialog.setViewMode(QFileDialog::List);
    m_dialog.setAcceptMode(QFileDialog::AcceptOpen);
    

    Unfortunately, I still can write a filename by hand in the textbox and it will be opened even if its extension is not listed in the setNameFilter arguments.

    I thought that maybe that's the 'feature' of the windows native window, so I set

    m_dialog.setOption( QFileDialog::DontUseNativeDialog);
    

    and 'Open' button in the dialog became disabled. Unfortunately, writing filename by hand and pressing 'Enter' still opens incorrect file.

    So I have to filter by extension twice.

    I just want to know, if that behaviour is normal or if it's a bug in Qt.


  • Lifetime Qt Champion

    Hi,

    What version of Qt are you using on which platform ?



  • @SGaist I'm using QT 5.7.1 on Windows.


  • Lifetime Qt Champion

    Can you validate that with a more recent version of Qt ?

    Note that I suspect that it's a Windows specific behaviour. By default Qt uses the native file dialog which may have some quirks.



  • @Amomum
    You want the filter to actually prevent a user from being able to specify a filename with a certain extension. But I don't think "filters" have ever claimed to do that. From the docs:

    In the above example, the filter is set to "Images (*.png *.xpm *.jpg)", this means that only files with the extension png, xpm, or jpg will be shown in the QFileDialog.

    I think they only determine what filenames are shown for selection. If the user types something, I don't they have anything to do with validating the response.

    So, yes, for safety you have to validate the final result yourself if it matters.


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