private void Box2_SelectedIndexChanged(object sender, EventArgs e)
{
DataTable dt = dm.getDataSet().Tables[0];
string value = Box2.GetItemText(Box2.SelectedItem);
List <string> cities = new List <string>();
dt.DefaultView.RowFilter = string.Format("[{0}] LIKE '%{1}%'", Box1.SelectedItem, value);
showMarkers(cities, value, dt);
}
