Picker for Countries Term Set

CountryPickerPage.cs

 public class CountryPickerPage : LayoutsPageBase
    {

        protected override void OnInit(EventArgs e)
        {
            continentsControl.AutoPostBack = true;
            continentsControl.SelectedIndexChanged += ContinentsControlChanged;
            base.OnInit(e);
        }

      


        protected override void OnLoad(EventArgs e)
        {
            var session = new TaxonomySession(SPContext.Current.Site, false);
            if(!Page.IsPostBack)
            {
                var countriesTermSet = InitContinentsControl(session);
                InitCountriesControl(session, countriesTermSet,null);
            }
            base.OnLoad(e);
        }



    


        private TermSet InitContinentsControl(TaxonomySession session)
        {
            var termStore = session.DefaultKeywordsTermStore;
            var groupSE = termStore.Groups["Geography"];
            var countriesTermSet = groupSE.TermSets["Countries"];
            if (countriesTermSet != null)
            {
                var countriesTerms = countriesTermSet.Terms;
                continentsControl.DataTextField = "Name";
                continentsControl.DataValueField = "Id";
                continentsControl.DataSource = countriesTerms;
                continentsControl.DataBind();
            }
            return countriesTermSet;
        }

        private void InitCountriesControl(TaxonomySession session, TermSet countriesTermSet, Term continentTerm)
        {
            if (countriesTermSet != null)
            {
                this.countryControl.SSPList = countriesTermSet.TermStore.Id.ToString();
                this.countryControl.TermSetList = countriesTermSet.Id.ToString();
            }
            else if (continentTerm != null)
            {
                this.countryControl.SSPList = continentTerm.TermStore.Id.ToString();
                this.countryControl.AnchorId = continentTerm.Id;
                this.countryControl.TermSetList = continentTerm.TermSet.Id.ToString();
            }      
        }





        void ContinentsControlChanged(object sender, EventArgs e)
        {
            var control = sender as DropDownList;
            if (control != null)
            {
                var continentTermId = new Guid(control.SelectedValue);
                var session = new TaxonomySession(SPContext.Current.Site, false);
                var termStore = session.DefaultKeywordsTermStore;
                var continentTerm = termStore.GetTerm(continentTermId);
                InitCountriesControl(session, null, continentTerm);
            }
           
        }

     

        protected TaxonomyWebTaggingControl countryControl;
        protected DropDownList continentsControl;

    }