private string AddParkingSpace(string formData) { _baseBLL.BeginTransaction(); try { dynamic attr = formData.ToJson<dynamic>(); int num = JZ.Tools.StringHelper.ConvertToInt(attr["num"].ToString()); string noFixPart = attr["noFixPart"].ToString(); string houseClassifyId = attr["houseClassifyId"].ToString(); string finalNumPart = ""; for (int i = 0; i < num; i++) { finalNumPart = GetNoNumberPart(attr["noNumberPart"].ToString(), i); string no = noFixPart + finalNumPart; ObjectModel parkingObj = SelectParkingSpace(no); if (!string.IsNullOrEmpty(parkingObj.ObjectID)) { _baseBLL.RollbackTransaction(); throw new Exception("车位号" + no + "重复，请检查车位号"); } ObjectModel obj = ObjectHelper.GetObjectModel(parkingSpace_clsName); SetAttrValue(obj, formData); obj.SetAttrValue("BH", no); SetSFFLValue(obj); _baseBLL.Add(obj); RelationModel rel = ObjectHelper.GetRelationModel(houseClassifyToCarport_clsName); NewRel(rel, houseClassifyId, obj.ObjectID); } _baseBLL.CommitTransaction(); return ""; } catch (Exception ex) { _baseBLL.RollbackTransaction(); throw ex; } }帮我注释一下上面的代码，谢谢

以下是对上述代码的注释：

// 定义一个私有方法 AddParkingSpace 并且接受一个字符串类型的 formData 参数
private string AddParkingSpace(string formData)
{
    // 开始事务
    _baseBLL.BeginTransaction();
    try
    {
        // 将 formData 转换为动态对象
        dynamic attr = formData.ToJson<dynamic>();
        // 从 formData 中获取 num、noFixPart 和 houseClassifyId 等属性
        int num = JZ.Tools.StringHelper.ConvertToInt(attr["num"].ToString());
        string noFixPart = attr["noFixPart"].ToString();
        string houseClassifyId = attr["houseClassifyId"].ToString();
        string finalNumPart = "";
        // 循环 num 次
        for (int i = 0; i < num; i++)
        {
            // 获取 finalNumPart
            finalNumPart = GetNoNumberPart(attr["noNumberPart"].ToString(), i);
            // 拼接车位号
            string no = noFixPart + finalNumPart;
            // 查询是否存在该车位
            ObjectModel parkingObj = SelectParkingSpace(no);
            if (!string.IsNullOrEmpty(parkingObj.ObjectID))
            {
                // 如果存在，则回滚事务并抛出异常
                _baseBLL.RollbackTransaction();
                throw new Exception("车位号" + no + "重复，请检查车位号");
            }
            // 创建一个 ObjectModel 对象
            ObjectModel obj = ObjectHelper.GetObjectModel(parkingSpace_clsName);
            // 设置属性值
            SetAttrValue(obj, formData);
            obj.SetAttrValue("BH", no);
            SetSFFLValue(obj);
            // 添加到数据库中
            _baseBLL.Add(obj);
            // 创建关联关系
            RelationModel rel = ObjectHelper.GetRelationModel(houseClassifyToCarport_clsName);
            NewRel(rel, houseClassifyId, obj.ObjectID);
        }
        // 提交事务
        _baseBLL.CommitTransaction();
        return "";
    }
    catch (Exception ex)
    {
        // 回滚事务并抛出异常
        _baseBLL.RollbackTransaction();
        throw ex;
    }
}