Conditional display of QComboBox in QTCreator - qt

Question

I am new to QT and GUI related programming and looking to do a 2 tier selection menu in a project. I appreciate the time taken to help.
Example: Combo box 1 has options like: 1. Screen size - Medium 2. Screen size - large and depending on that I would like to display different options for screen resolution in combo box 2.
The user can change the combo box 1 selection any number of times and box 2 should show the appropriate options.
I have tried using QComboBox.setEnabled(False) and True as was suggested in Disabling QComboBox in pyqt
but it has not worked for me and I am certainly missing something.
Snippet of my code:
void interface::changeFunctionx(int index)
{
delete f;
switch(index)
{
case 0:
version = 1;
functionSely->setVisible(1);
break;
case 1:
version = 1;
//some other function call still seeing how gui works
break;
}
}

Answer 1

The Data of the QComboBox can be re-filled using below logic
QComboBox::clear()
QComboBox::insertItems(0,QStringList);
//Declare the variable needed in the class
class myclass : public QMainWindow {
QList<QString> lst;
QStringList ql1,ql2;
}
Two combo box used in this example. i.e, cbo1 (2 items) (user selection) & cbo2 (re-fill data)
//Combo box fill Data Preparation
//In this example, the below function called only one time (called from the end line of constructor) (to initialize)
void fnPrepareStaticData(){
lst.push_back("Option-1");
lst.push_back("Option-2");
lst.push_back("Option-3");
ql1 = (QStringList(lst));
lst.clear();
lst.push_back("New-1");
lst.push_back("New-2");
lst.push_back("New-3");
ql2 = (QStringList(lst));
}
//slot added to the QComboBox (currentIndexChanged(int index))
void MainWindow::on_cbo1_currentIndexChanged(int index)
{
ui->cbo2->clear();
switch (index) {
case 0:
ui->cbo2->insertItems(0,ql1);
break;
case 1:
ui->cbo2->insertItems(0,ql2);
break;
default:
break;
}
}