PyQt Custom QAbstractTableModel for combobox - pyqt

Question

In the following sample code I want to use a QDataWidgetMapper together with a Combobox to display data retrieved from a database.
Unfortunately I can't e.g. preselect the choice of the combobox and I can't retrieve the database id on selecting a value in the combobox. Therefore I think I am really missing something fundamental here.
I reduced my program to this sample code which I hope illustrates my problem.
import sys
from PyQt4 import QtGui
from PyQt4 import QtCore
class ComboModel(QtCore.QAbstractTableModel):
def __init__(self, parent=None, *args):
super(ComboModel, self).__init__()
# The data would normally be read from a database (not using the Qt SQL classes)
self.dbIds = [ 13, 49, 81 ]
self.dbValues = [ 'Value 1', 'Value 2', 'Value 3' ]
def rowCount(self, parent=QtCore.QModelIndex()):
if parent.isValid():
return 0
return len(self.dbIds)
def columnCount(self, parent=QtCore.QModelIndex()):
if parent.isValid():
return 0
return 2
def data(self, index, role=QtCore.Qt.DisplayRole):
print 'ComboModel data'
if not index.isValid() or ( role != QtCore.Qt.DisplayRole and role != QtCore.Qt.EditRole ):
print 'ComboModel return invalid QVariant'
return QtCore.QVariant()
if index.column() == 0:
return QtCore.QVariant(self.dbIds[index.row()])
if index.column() == 1:
return QtCore.QVariant(self.dbValues[index.row()])
print 'ComboModel return invalid QVariant'
return QtCore.QVariant()
class TableModel(QtCore.QAbstractTableModel):
def __init__(self, parent=None, *args):
super(TableModel, self).__init__()
self.editValue = 'Value to edit'
self.comboValue = 49 # This is the database id of the selected entry
def rowCount(self, parent=QtCore.QModelIndex()):
if parent.isValid():
return 0
return 1
def columnCount(self, parent=QtCore.QModelIndex()):
if parent.isValid():
return 0
return 2
def data(self, index, role=QtCore.Qt.DisplayRole):
print 'TableModel data'
if not index.isValid() or ( role != QtCore.Qt.DisplayRole and role != QtCore.Qt.EditRole ):
print 'TableModel return invalid QVariant'
return QtCore.QVariant()
if index.column() == 0:
return QtCore.QVariant(self.editValue)
if index.column() == 1:
return QtCore.QVariant(self.comboValue)
print 'TableModel return invalid QVariant'
return QtCore.QVariant()
def setData(self, index, value, role=QtCore.Qt.DisplayRole):
print 'TableModel setData'
if not index.isValid():
return False
if index.column() == 0:
print 'new Value: ' + value.toString()
self.editValue = value.toString()
if index.column() == 1:
print 'new combobox value'
print 'new Value: ' + value.toString()
self.comboValue = value.toString() # how do I get the dbId?
return True
class MainWindow(QtGui.QWidget):
def __init__(self, parent=None):
QtGui.QWidget.__init__(self, parent)
self.setGeometry(300, 300, 250, 150)
self.setWindowTitle('Test')
self.edit = QtGui.QLineEdit(self)
self.edit.setGeometry(10, 40, 80, 30)
self.combo = QtGui.QComboBox(self)
self.combo.setGeometry(10, 80, 80, 30)
self.combo_model = ComboModel()
self.combo.setModel(self.combo_model)
self.combo.setModelColumn(1)
self.model = TableModel()
self.mapper = QtGui.QDataWidgetMapper()
self.mapper.setModel(self.model)
self.mapper.addMapping(self.edit, 0)
self.mapper.addMapping(self.combo, 1)
self.mapper.toFirst();
app = QtGui.QApplication(sys.argv)
window = MainWindow()
window.show()
app.exec_()