private void findPartnersMenuItem_Click(object sender, EventArgs e)
 {
     searchTextBox.Clear();
     clearSearchResults();
     resultsTree               = mainTree.FindTradePartners(selectedCountry);
     searchBoxLabel.Text       = "Displaying all Trade Partners for " + selectedCountry.Name + ": " + resultsTree.Count();
     countryList.DataSource    = resultsTree.GetCountries();
     countryList.DisplayMember = "name";
     backButton.Enabled        = true;
 }
        public CountryTree FindTradePartners(Country searchTerm)
        {
            CountryTree tradePartners = new CountryTree();

            foreach (string partner in searchTerm.MainTradePartners)
            {
                foreach (Country country in GetCountries())
                {
                    if (country.Name.Equals(partner))
                    {
                        tradePartners.InsertItem(country);
                    }
                    else if (country.MainTradePartners.Contains(searchTerm.Name) && !tradePartners.Contains(country))
                    {
                        tradePartners.InsertItem(country);
                    }
                }
            }
            return(tradePartners);
        }