Recursive filtering on QSortFilterProxy

[wejgomi]

Hi,

I have hierarchial data in my QStandardItemModel model which is applied to a QTreeView. As for the hierarchy , its depth level is 3 :

first_level_node
		second_level_node
			third_level_node

I want to apply QSortFilterProxyModel to it : If the filter does not match first_level_node's text but if it matches second_level_node or third_level_node , also that first_level_node should stay visible.

How can I achieve that ?

I made an attempt by calling setRecursiveFilteringEnabled , however that make entire rows invisible.

QObject::connect(m_filtering_line_edit, &QLineEdit::textChanged, m_proxy_model, [&](const QString& text) 
 {
     if (text.isEmpty()) 
     {
         m_treeview->setModel(m_model);
         m_treeview->collapseAll();
     }
     else
     {
         QRegularExpression filter("^" + QRegularExpression::escape(text), QRegularExpression::CaseInsensitiveOption);
		 

         m_proxy_model->setFilterRegularExpression(filter);
         m_proxy_model->setFilterKeyColumn(0);
         m_proxy_model->setRecursiveFilteringEnabled(true);

         m_treeview->setModel(m_proxy_model);
     }
 });

Many thanks

[JonB]

@wejgomi
Per the docs

This property holds whether the filter to be applied recursively on children, and for any matching child, its parents will be visible as well.

and I have found that works as documented. If a child matches it is made visible and that means its parents are also visible. So what does your "make entire rows invisible." mean?

[wejgomi]

@JonB Sorry, I should have clarified. In my data model , there is only a single column , therefore I was referring to all model items as "rows". In other words, when I apply the filter with the regexp in the code, even when I enter a valid text , nothing is visible after filter processing . If the model data is :

aa 
   bb

And when I type b ( QString& text in the lambda expression ) , I am expecting to see :

aa 
   bb

Therefore I have asked the question that way assuming my expectation is correct.

[wejgomi]

I have found the issue. I was mising that -> m_proxy_model->setSourceModel(m_model);

[JonB]

@wejgomi
That is a pretty fundamental omission! Then I don't see how you had it working before you added the filter/setRecursiveFilteringEnabled() at all.