Widget _buildVerticalLetterCascader(BuildContext context) {
    return GestureDetector(
      onTap: () {
        TDCascader.showMultiCascader(context, title: '选择地址', data: _data_2, initialData: _initData_2, theme: 'step',
            onChange: (List<MultiCascaderListModel> selectData) {
          setState(() {
            List result = [];
            int len = selectData.length;
            _initData_2 = selectData[len - 1].value!;
            selectData.forEach((element) {
              result.add(element.label);
            });
            _selected_2 = result.join('/');
          });
        }, onClose: () {
          Navigator.of(context).pop();
        });
      },
      child: _buildSelectRow(context, _selected_2, '选择地区'),
    );
  }