WPF Combox使用 Text无法选择正确获取CHange后的Text

使用固定ComboxItem 无法通过 selectitem as object 来进行回去到 Content内的对香数据。那我只能这个样干：

 private void CBPaiweiLeixingSelect_Change(object sender, SelectionChangedEventArgs e)
        { 
            ComboBox ThisBox = sender as ComboBox;
            List<EDaxiaosuixi> ListShuixiE;
            ComboBoxItem SelectItemTextBox = CBPaiweiType.SelectedItem as ComboBoxItem;
            string SelectItemstr = SelectItemTextBox.Content as string;
            if (SelectItemstr == "非吉祥牌位")
            {
                ListShuixiE = ThisPaiweilist.Where(x => x.PaiweiType != EPaiweiType.吉祥牌位).Select(x => x.DaxiaoSuixi).Distinct().ToList();//获取大小随喜 
                CBPaiweiGuige.ItemsSource = ListShuixiE;
            }
            else if (SelectItemstr == "吉祥牌位")
            {
                ListShuixiE = ThisPaiweilist.Where(x => x.PaiweiType == EPaiweiType.吉祥牌位).Select(x => x.DaxiaoSuixi).Distinct().ToList();//获取大小随喜 
                CBPaiweiGuige.ItemsSource = ListShuixiE;
            }
        }

使用这个方法：

 List<EDaxiaosuixi> ListShuixiE;
        ComboBoxItem SelectItemTextBox = CBPaiweiType.SelectedItem as ComboBoxItem;
        string SelectItemstr = SelectItemTextBox.Content as string;

SelectItemstr 就是要获取的便跟过来的数据。