Populate Combobox from a list

There's one issue with visual controls updating (such as ComboBox etc): you'd rather prevent them from re-painting at each data change (at each item addition in your case):

cmbMovieListingBox.BeginUpdate(); // <- Stop painting

try {
  // Adding new items into the cmbMovieListingBox 
  foreach(var item in LoadListings())
    cmbMovieListingBox.Items.Add(item.GetFilmTitle());
finally {
  cmbMovieListingBox.EndUpdate(); // <- Finally, repaint if required
}

Remove the {get; set;} from the list declaration. It's not needed there.

Define your class like this:

public class Listing
{
    private String filmTitle {get; set;}
    private String description {get; set;};
    …
}

On the form load event set the ComboBox DisplayMember and ValueMember to "filmTitle"

cmbMovieListingBox.DisplayMember = "filmTitle";
cmbMovieListingBox.ValueMember = "filmTitle"

Finally, you must set the DataSource of the ComboBox to the list

cmbMovieListingBox.DataSource = films;

And there you have it. The rest of your code should function now.

if you are asking what i think you are asking, you need something like this in your form load:

foreach(Listing listing in LoadListings()){
    cmbMovieListingBox.Items.Add(listing.GetFilmTitle());
}

I would hold List<Listing> at the class level so you can access it when a user clicks on it. I would also throw this on it's own thread and not directly in the Load event. If it's a long process you will hang the ui.

private List<Listing> films { get; set; }

Load

films = LoadListings();
foreach (Listing film in films)
{
    cmbMovieListingBox.Items.Add(film.GetFilmTitle());
}

When the user selects the item

Listing film = films.Where(f => f.GetFilmTitle().Equals(cmbMovieListingBox.SelectedValue)).FistOrDefault();

if (film != null)
{
    //do work
}