Python Hierarchical QcomboBox: clean-up list

Question

Hi Everybody,

I have a hierarchical two combo-box. The first combo-box displays a list of customerNames, i.e. different companies from a MySQL db. Each customer has branches in different cities.

Then, when a customer name is chosen from combo-box1 option list, e.g. {Aldi, Meyer, Carrefour, WalMart}, for that particular customer, a list of cities/branches is automatically displayed in the combo-box2. Something like that, e.g.:

combo1: chosen_customer [Aldi] --> cities:{NY, Boston, Berlin, Tokyo, London} then..
combo2: options {NY, Boston, Berlin, Tokyo, London}

The problem comes when we chose again another customer, that eventually has a smaller number of branches - e.g.

combo1: chosen_customer [Meyer] --> {LA, San Francisco}, then.. we got
combo2: options {LA, San Francisco, Berlin, Tokyo, London}

intead of combo2: options {LA, San Francisco}

Here is the function that runs the combo2, which is called every time a customerName is chosen from the list combo1:

def loadComboCity(self,customerName):
    """query results cityList into self.mydb.matrix"""
    queryName="citylist_thisCustomer"
    self.mysqlAPI(queryName,customerName)

    id=0
    for row in self.mydb.matrix:
        cityname=self.mydb.matrix[id][0]
        self.addcomboCity(id,cityname) 
        id=id+1
    del self.mydb.matrix[:]

and the function that adds each name of the list city that belongs to that customer:

def addcomboCity(self,id,cityname):
    self.comboCity.addItem(QtCore.QString())
    self.comboCity.setItemText(id, QtGui.QApplication.translate("MainWindow", cityname, None, QtGui.QApplication.UnicodeUTF8))

We tried to use del to clean the previous content of the list, but it still gets the same behavior.

This is a Qt or a Python related problem? Or there is some bit that we are missing here?

All comments and suggestions are highly appreciated.

Answer 1

I think you are missing a QComboBox.clear() call , before the 'for loop'. Try the following code (Notice the new line just before id=0)

def loadComboCity(self,customerName):
    """query results cityList into self.mydb.matrix"""
    queryName="citylist_thisCustomer"
    self.mysqlAPI(queryName,customerName)

    # Clear the previous items in the combobox (if any)
    self.comboCity.clear()

    id=0
    for row in self.mydb.matrix:
        cityname=self.mydb.matrix[id][0]
        self.addcomboCity(id,cityname) 
        id=id+1
    del self.mydb.matrix[:]