[PyQt] How to select a row in treeview

[IT]

Hi all, a newbie and throughly enjoying pyqt; but and a little  problem.

I've got a treeview/model which is loaded via json.

I want to select a row in code, eg after a refresh of data to restore 
the previous row or to select a new one.

The problem I'm having is that I can seem to be able to select a row 
properly, it ends up being a single cell which throws and error in the 
selectionChanged() handler. Am also a bit confused how to create 
modelIndex's that span a row.

Can anyone help please, tia
pete

        
##########################################################################
        ##  Model
        self.model = QtGui.QStandardItemModel(0, 3, self)
        self.model.setHeaderData(wTestCategoryColumns.test_category_id, 
QtCore.Qt.Horizontal, QtCore.QVariant("#"))
        
self.model.setHeaderData(wTestCategoryColumns.test_category_item, 
QtCore.Qt.Horizontal, QtCore.QVariant("Item"))
        self.model.setHeaderData(wTestCategoryColumns.test_category, 
QtCore.Qt.Horizontal, QtCore.QVariant("Test Category"))


        
##########################################################################
        ##  Tree
        self.tree = QtGui.QTreeView()
        #self.tree.setModel( self.proxyModel )
        self.tree.setModel( self.model )
        self.tree.setSortingEnabled(True)
        self.tree.sortByColumn( 2 )
       
        self.tree.header().setStretchLastSection( True )
        self.tree.setRootIsDecorated(False)
        self.tree.setAlternatingRowColors(True)

        self.tree.setSelectionBehavior( QtGui.QAbstractItemView.SelectRows )
        self.tree.setSelectionMode(QtGui.QTreeView.ExtendedSelection)

        sm = self.tree.selectionModel()
        self.connect(sm, QtCore.SIGNAL('selectionChanged(const 
QItemSelection&,const QItemSelection&)'), self.on_selection_change)

##########################
## Selection change
    def on_selection_change(self, newSelection, oldSelection):
        ### If its selected below, then this bombs out as the indexes 
ain't there ie complete row
        print "new=", newSelection.indexes()
        self.params['test_category_id'] = int( self.model.itemFromIndex( 
newSelection.indexes()[0] ).text() )
        self.params['test_category']    = self.model.itemFromIndex( 
newSelection.indexes()[2] ).text()


### LOAD .. and this is where one is confused .....
        if row_to_select:
            modelIndexL = self.model.createIndex( row_to_select, 0)
            modelIndexR = self.model.createIndex( row_to_select, 2)
            #print "mi=", modelIndexL, modelIndexR
            
self.tree.selectionModel().select(QtGui.QItemSelection(modelIndexL, 
modelIndexR), QtGui.QItemSelectionModel.Columns)
            #self.tree.selectionModel().setCurrentIndex( modelIndexL , 
QtGui.QItemSelectionModel.Rows ) # < tried Columns/Select etc ;-(