/// 
       /// 下拉框改变事件：获取下拉框中当前选择的文本       /// 
       ///        ///        private string myComboBox_SelectionChanged(object sender, SelectionChangedEventArgs e)       {           try           {               object obj = (object)e.AddedItems;                          string str= Convert.ToString(((System.Data.DataRowView)(((object[])(obj))[0])).Row.ItemArray[1]);                              return str;           }           catch (Exception)           {               throw;           }       }