Access original index in QAbstractTableModel from selected row in QTableView

Question

I am implementing a GUI for a python programme using Qt5 and PySide2. I have no problem understanding the C++ side of Qt, so feel free to point out Qt references not related with python.

I have some data that I display in a QTableView using a subclass of QAbstractTableModel. I also use a subclass of QSortFilterProxyModel to filter my table to only display a subset of the underlying data because it's a very large dataset. I offer the user the possibility to display only part of this data according to some criteria. This all works really well.

Then I have configured the QTableView so that the user can only select complete rows:

self.ui.candidatesTable.setSelectionBehavior(QTableView.SelectRows)

And in the object handling the UI I have implemented a slot that is called when the selection in the table changes:

@Slot(QItemSelection)
def handleSelectionChanged(self, item):
    hasSelection = self.ui.candidatesTable.selectionModel().hasSelection()
    if hasSelection:
        selectedRows = self.ui.candidatesTable.selectionModel().selectedRows()
        for row in selectedRows:
            print(row.row())

My problem is that the value printed by print(row.row()) shows the row index in the currently displayed rows. If the user has selected filtering criteria that only displays 5 rows out of the several thousands, and then selects the first row, print(row.row()) will return 0 and not the original index in the underlying QAbstractTableModel.

My question is therefore the following: how can I access the original index in this situation?

Answer 1

You have to map the QModelIndex of the proxy model to the source model using the mapToSource() method:

@Slot(QItemSelection)
def handleSelectionChanged(self, item):
    indexes = self.ui.candidatesTable.selectedIndexes()
    proxy_model = self.ui.candidatesTable.model()    

    rows = set()
    for index in indexes:
        si = proxy_model.mapToSource(index)
        rows.add(si.row())

    for row in rows:
        print(row)