How to set QStyle::SH_ComboBox_Popup to false?

[CJha]

I am using fusion style on windows. In this style the QComboBox is ignoring the maxVisibleItems property:

Note: This property is ignored for non-editable comboboxes in styles that returns true for QStyle::SH_ComboBox_Popup such as the Mac style or the Gtk+ Style.

I have around 150 entries in my combo-box and when I click on it, the combo-box expands from top to bottom of my monitor. How can I set the QStyle::SH_ComboBox_Popup property to false? There is no setStyleHint() function in QStyle class. Is there another way to get around this weird issue?

[raven-worx]

@CJha
have you already seen the QProxyStyle class?

[CJha]

@raven-worx Yes, but I am unable to understand how to override this in QProxyStyle class.

[CJha]

Thanks to @raven-worx I figured it out using QProxyStyle, here is my code:

class MyProxyStyle : public QProxyStyle
{
public:
    int styleHint(StyleHint hint, const QStyleOption* option = nullptr,
                  const QWidget* widget = nullptr, QStyleHintReturn* returnData = nullptr) const override
    {
        if(hint == QStyle::SH_ComboBox_Popup)
            return 0;
        return QProxyStyle::styleHint(hint, option, widget, returnData);
    }
};

[raven-worx]

@CJha
yes, where is the problem exactly?
But i am anyway not sure if you get what you want just by simply switching a flag.

Another approach would be to subclass QComboBox and overrride the virtual showPopup() method.
In there call the base class implementation and afterwards resize and reposition the popup window.

You can get the popu window with comboBox->view()->window()

[CJha]

@raven-worx For me, it seems as it is working. The above code is actually taken from ProxyStyle web page from Qt's website, I just replaced QStyle::SH_UnderlineShortcut with QStyle::SH_ComboBox_Popup. So, I think it is a good approach.

Subclassing QComboBox would become quite cumbersome as I will have to promote all the combo boxes in my UI to the subclass.