public Form1() { InitializeComponent(); CountryCollection countryCollection = new CountryCollection(); cboCountry.DataSource = countryCollection.GetCountries(); cboCountry.DisplayMember = "CountryName"; cboCountry.ValueMember = "CountryId"; StateCollections stateCollections = new StateCollections(); cboState.DataSource = stateCollections.GetStates(); cboState.DisplayMember = "StateName"; cboState.ValueMember = "StateId"; }