asp.net - 通过 LINQ 语句返回记录

Question

DataContext db = new DataContext();
Select_Utilities SelectedUtility = (from su in db.Select_Utilities
                                    where su.id == SelectUtilityId
                                    && su.Worksite_Id == WorksiteId
                                     && su.Utility_Company.id == UtilityCompanyId
                                     select su).FirstOrDefault();

然后我想说 SelectedUtility.comment = "无论评论是什么";

但是出现错误：无法将类型“Select_Utility”隐式转换为“Select_Utilities”

声明中带有“FirstOrDefault”....有什么建议吗？

谢谢

Answer 1

将结果类型更改为Select_Utility

Select_Utility SelectedUtility =  // here
   (from su in db.Select_Utilities
    where su.id == SelectUtilityId && 
          su.Worksite_Id == WorksiteId && 
          su.Utility_Company.id == UtilityCompanyId
    select su).FirstOrDefault();

Answer 2

我猜Select_Utilities是你的实体表的名称，它包含一组Select_Utility对象。尝试：

Select_Utility selectedUtility = (from su in db.Select_Utilities
                                  where su.id == SelectUtilityId
                                     && su.Worksite_Id == WorksiteId
                                     && su.Utility_Company.id == UtilityCompanyId
                                  select su).FirstOrDefault();