Issue getting information from database into variable

ok, so i have got a dropdownlist, which contains a number from a database(the amount of seats taken). If the rest of the dropdownboxes change(the flight arrival/departure), the dropdown box with the seats taken box changes to the correct piece of data associated with that flight I am trying to store the seats taken into a variable, however, the number which is stored is the number from the previous value that was in the dropdown box and not the updated value

Is there a way i can get the new updated number into the variable?

Sorry for not being clear :/

    int flightsTaken;
    string departure, arrival;

    departure = Convert.ToString(DropDownListDepartures.Text);
    arrival = Convert.ToString(DropDownListArrivals.Text);

    //Sets up how many flights are availabe for each departure place
    if (departure == "London (Ltn)")
        flightsAvailable = 12;
    else if (departure == "Edinburgh")
        flightsAvailable = 3;
    else if (departure == "Manchester")
        flightsAvailable = 6;


    flightsTaken = Convert.ToInt32(DropDownList2.Text);  //THIS GETS THE PREVIOUS NUMBER NOT THE CURRENT NUMBER
    flightsAvailable -= flightsTak开发者_如何学Goen;

Where are you assigning the value of this dropdown box? It would need to be done on pageload OR any dropdownbox_change event. A postback will only run the page_load and the event fired.

The best option is to tie the update to the drowdown_change event to update the values of any other dropdown boxes that rely on it's value.