How to find Combo box selected item index?

Hi 

I am facing difficulty in using the Combo boxes in my Windows application. The goal is to :- "Read all the options, find out the selected index and set a new index". 

The combo boxes in question have the following architecture -  ComboBox -> ListItems (un-identifiable) -> Text(the string value). 

My idea is to read all children of combo box (loop), then read children of each ListItem(loop) and then find out the selected index thus knowing which option has been selected . Later change it as per requirement.

For doing so I need to store ComboBoxs and  ListItems as different variables, how can this be done?

Also I have multiple combo boxes in same page and also in other pages how to identify each as a different, right now I am unable to identify them at all. 

Thanks in advance for yout help.

Regards

Chetan