LinqtoSQL过滤器和语法顺序

时间:2020-03-06 14:56:45  来源:igfitidea点击:

我的Techie Bretheren(当然还有Sisteren!),

我有一个具有以下实体的LinqToSql数据模型:
数据模型http://danimal.acsysinteractive.com/images/advisor.jpg

我需要检索特定办公室的所有顾问,并按他们在办公室中的顺序排序。我已经有了与联接一起工作的第一部分:

public static List<Advisor>GetOfficeEmployees(int OfficeID)
{
    List<Advisor> lstAdvisors = null;
    using (AdvisorDataModelDataContext _context = new AdvisorDataModelDataContext())
    {
        var advisors = from adv in _context.Advisors
                       join advisoroffice in _context.OfficeAdvisors
                           on adv.AdvisorId equals advisoroffice.AdvisorId
                       where advisoroffice.OfficeId == OfficeID
                       select adv;

        lstAdvisors = advisors.ToList();

    }
    return lstAdvisors;
}

但是,我似乎无法将我的疲倦的大脑包裹在order by子句的周围。任何人都可以提出一些建议吗?

解决方案

from adv in _context.Advisors
where adv.OfficeAdvisor.Any(off => off.OfficeId == officeID)
order adv by adv.OfficeAdvisor.First(off => off.OfficeId = officeID).Sequence
select adv;

public static List<Advisor>GetOfficeEmployees(int OfficeID)
{
    List<Advisor> lstAdvisors = null;
    using (AdvisorDataModelDataContext _context = new AdvisorDataModelDataContext())
    {
        var advisors = from adv in _context.Advisors
                       join advisoroffice in _context.OfficeAdvisors
                           on adv.AdvisorId equals advisoroffice.AdvisorId
                       where advisoroffice.OfficeId == OfficeID
                       group adv by adv.OfficeId into g
                       order by g.Sequence
                       select g;

        lstAdvisors = advisors.ToList();

    }
    return lstAdvisors;
}

注意:我目前无法在Visual Studio上对此进行测试,但应该可以使用。

我们可以像这样添加order by子句:

var advisors = from adv in _context.Advisors
                  join advisoroffice in _context.OfficeAdvisors
               on adv.AdvisorId equals advisoroffice.AdvisorId
               where advisoroffice.OfficeId == OfficeID
               orderby advisoroffice.Sequence //  < -----
               select adv;