代码之家 › 专栏 › 技术社区 › Niels Bosma

LINQ查询有问题

linq-to-sql c#

Niels Bosma · 技术社区 · 15 年前

以下工作正常:

                    (from e in db.EnquiryAreas
                            from w in db.WorkTypes
                            where
                            w.HumanId != null &&
                            w.SeoPriority > 0 &&
                            e.HumanId != null &&
                            e.SeoPriority > 0 &&
                            db.Enquiries.Where(f => 
                                f.WhereId == e.Id && 
                                f.WhatId == w.Id && 
                                f.EnquiryPublished != null && 
                                f.StatusId != EnquiryMethods.STATUS_INACTIVE &&
                                f.StatusId != EnquiryMethods.STATUS_REMOVED &&
                                f.StatusId != EnquiryMethods.STATUS_REJECTED &&
                                f.StatusId != EnquiryMethods.STATUS_ATTEND
                            ).Any()
                            select
                            new
                            {
                                EnquiryArea = e,
                                WorkType = w
                            });

但是:

               (from e in db.EnquiryAreas
                            from w in db.WorkTypes
                            where
                            w.HumanId != null &&
                            w.SeoPriority > 0 &&
                            e.HumanId != null &&
                            e.SeoPriority > 0 &&
                            EnquiryMethods.BlockOnSite(db.Enquiries.Where(f => f.WhereId == e.Id && f.WhatId == w.Id)).Any()
                            select
                            new
                            {
                                EnquiryArea = e,
                                WorkType = w
                            });

   public static IQueryable<Enquiry> BlockOnSite(IQueryable<Enquiry> linq)
    {
        return linq.Where(e => 
            e.EnquiryPublished != null && 
            e.StatusId != STATUS_INACTIVE &&
            e.StatusId != STATUS_REMOVED &&
            e.StatusId != STATUS_REJECTED &&
            e.StatusId != STATUS_ATTEND
        );
    }

我得到以下错误:

基System.SystemException:“方法”System.Linq.iQueryable 1[X.Enquiry] BlockOnSite(System.Linq.IQueryable 1[x.enquiry])'不支持转换为SQL。“

2 回复 | 直到 14 年前

bruno conde 15 年前

linq to sql只将某些方法调用转换为sql,而您的方法调用( BlockOnSite )不是他们中的一个。因此出现了错误。你的方法需要 IQueryable<T> 返回一个 可查询 这并不特别。

Niels Bosma 15 年前

好的,我用以下方法解决了它:

        IQueryable<Enquiry> visibleOnSite = EnquiryMethods.VisibleOnSite(db.Enquiries);

        var combinations = (from e in db.EnquiryAreas
                            from w in db.WorkTypes
                            where
                            w.HumanId != null &&
                            w.SeoPriority > 0 &&
                            e.HumanId != null &&
                            e.SeoPriority > 0 &&
                            visibleOnSite.Where(f => f.WhereId == e.Id && f.WhatId == w.Id).Any()
                            select
                            new
                            {
                                EnquiryArea = e,
                                WorkType = w
                            });