public partial class Page : UserControl
 {
  public Page()
  {
   // 需要初始化变量
   InitializeComponent();
            
            this.myCbb.UpdateLayout();
            this.myCbb.SelectedIndex = 0;
  }

        public class Category
        {
            public int ID
            {
                get;
                set;
            }

            public string Name
            {
                get;
                set;
            }

            public int Count
            {
                get;
                set;
            }
        }

        void UserControl_Loaded(object sender, RoutedEventArgs e)
        {
            List<Category> ctg = new List<Category>()
            {
                new Category { ID=1, Name="成都", Count=028 },
                new Category { ID=2, Name="乐山", Count=0833 },
                new Category { ID=3, Name="北京", Count=010 },
                new Category { ID=4, Name="重庆", Count=023 }
            };

            this.myCbb.ItemsSource = ctg;
        }

        private void myCbb_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            Category cgy = this.myCbb.SelectedItem as Category;
            this.tblInfo.Text = "你选择的地区是:" + cgy.Name + "  区号为:" + cgy.Count;
        }
    }
}