Another error I'm getting that I can't understand is this one > ###### FATAL: ASSERT: "last < rowCount(parent)" in file itemmodels\qabstractitemmodel.cpp, line 2785 (itemmodels\qabstractitemmodel.cpp:2785, (null)) ###### ###### FATAL: ASSERT: "!this->isEmpty()" in file c:\users\qt\work\qt\qtbase\include\qtcore\../../src/corelib/tools/qstack.h, line 62 (c:\users\qt\work\qt\qtbase\include\qtcore\../../src/corelib/tools/qstack.h:62, (null)) ###### I went over entire drag/drop operation line by line checking indexes/ removeRow/insertRow routine and everything appear to be "valid" and yet I get this at the end ;[ This happens when I move last item from group in to another group, say item is index row 8 the function would be mGenericModel->beginRemoveRows(index(), 8, 8); ? or its 8 and 8+1 ? Else that assert is incorrect in library > Q_ASSERT(last < rowCount(parent)); Since if I'm moving last item, then last will be == rowCount(parent) which is still valid, and yet this will cause error :/ Or am I just talking total nonsense now... Ok went line by line, error happens latter. Size of children is 9, last item index is 8, everything clears up properly. The crash happens latter in Qt ;[ It looks like its the damn persistentIndexes/proxy models not getting notified properly.

breaks SOLID It doesn't. In fact, if it worked as you expected it would break SOLID it's definitely a serious design flaw Sorry to be brutal: No, it's not a flaw, you just didn't understand the design of model/views. To help you get a better idea of what is going on, try use the same model with 2 different treeviews. In only one of the view call setRootIndex, and then trigger the filtering.

So this needs a bump now, I tried using setRootIndex but that did not work... https://forum.qt.io/topic/102454/qtreeview-setrootindex-changing-header-incorrect-columncount/6 So I'm back to proxyModels... my main issue now is, how can I set a new rootIndex/item to that sortFilterProxy kick in from right infex and not from old index? As far as I can tell the filtering starts when tree request item, which usually is the root item, so header item. Since thats not the item I want to show I return false & since I return false there are no more items to query - thus no children thus the item that I actually want to show as new root never gets called/checked... if I use filterAcceptsRow() function... so where/who do I change to set different rootItem via proxy model?

You may also try to set dynamicSortFilter: true, but only if you do not modify contents of model through proxy model. invalidate() calls are expensive and you should only do it when you know what you are doing. If you modify contents of your model through proxy model and/or you need to filter and sort on demand, invalidateFilter() and sort() is what you are looking for.

@VRonin said in Implement QSortFilterProxyModel with own TreeModel?: Good guess, can you show us your code? I solved it: I had to pass the parent index (tree structure), so the line should look like this: QVariant data = m_proxy->data(m_proxy->index(index.row(), 4, index.parent()));

Ok I found what was causing this awful bug. When I check if the map contains the index, I actually check the raw index not the QPersistantModelIndex so this is not the same object and I think qmap does not check equality using == operator . So I have to iterate over the map and check using QPersistantModelIndex "==" operators which can compare from a QModelIndex.

@VRonin Thank you. Yesterday, I tried same things. But it was not working than later on I found, I forget to add file name in SOURCE , HEADER. Now it is work as expectation.

Thank you @mrjj and @Christian for answer. I am able to make user Checkable. class CustomListModel : public QStandardItemModel { public: Qt::ItemFlags CustomListModel::flags(const QModelIndex & index) const { Qt::ItemFlags defaultFlags = QStandardItemModel::flags(index); if (index.isValid()) { return defaultFlags | Qt::ItemIsUserCheckable; } return defaultFlags; } CustomListModel(const int row, const int coloumn) : QStandardItemModel(row, coloumn) { } }; and modification. hwListProxyModel->setSourceModel(new CustomListModel (0, 0));

@IMAN4K said in change QSortFilterProxyModel behaviour for multiple column filtering: Answer from stackfverflow : http://stackoverflow.com/questions/39488901/change-qsortfilterproxymodel-behaviour-for-multiple-column-filtering This answer is the typical example that lead people to say subclassing QSortFilterProxyModel, which would likely have a very limited reusability It's bad. the proxy model implementation should not depend on the structure of the underlying data in sourceModel

@Kofr mapFromSource() and mapToSource() are enough. The default implementation should depend on these methods only.

Problem Solved. CODE QModelIndex index2=proxymodel->mapToSource(index); //Returns the source model index (In my case it was QFileSystemModel) QString selectedrow=filemodel->fileInfo(index2).absoluteFilePath(); //filemodel is My QFileSystem Model.

Hi, Apply the same filter you are using for your single folder version except that this time rather than using a QString you should keep a QStringList of the folders you want to show and use that.

One possibility might be to use directoryLoaded.

Good ! Since you have it working now, please mark the thread as solved using the "Topic Tool" button so that other forum users may know a solution has been found :)

You have to register your custom types

You could stack two QSortFilterProxyModels on top of the each other, one filtering on the first column/value, and the other on the second column/value. Alternatively, you could subclass QSortFilterProxyModel to override filterAcceptsRow() and compare two columns against two filter values (the first is the existing column and value, and a second you add)

@mcosta QSqlQueryModel

I don't understand your question 1. With a QList of hidden column, you don't need to know the size of the array in your model and you don't need to loop through the complete array to know which columns are hidden or not. You just need to do something like if (!hiddenColumnList.contains(index.column())) { // do some stuff if column is not hidden }

@JDGXNV The delegates are recycled every-time you scroll which means there are created and destroyed as and when required internally (More here: delegate). Caching them disables it. So I guess the problem should be on the delegate side i.e the delegate is trying to access some property which it is not able and hence crashes.

@eagain said: @p3c0 I tried, but apparently im too blind to find that button. The "Topic Tools" only contain the option to "Delete Topic" At the moment, only moderators can mark topics as solved: http://forum.qt.io/topic/51926/real-quick-forum-things/4 Tero, our community manager, is looking to give every user that ability. In the meantime, I believe you can mark it by editing the original post and adding "[Solved]" to the start of the title.