Question

我有以下代码：

var catRoots = CatalogContext.CatalogRoots.Where(cr => cr.Visible);
var catChapter = CatalogContext.CatalogChapters.Where(cch => cch.Visible);
var catThemes = CatalogContext.CatalogThemes.Where(cth => cth.Visible);
var catCompanies = CatalogContext.CatalogCompanies.Where(cc => cc.Visible);
var catRelations = CatalogContext.CatalogCompanyThemeRelations.Where(cctr => cctr.Visible && cctr.OwnerVisible);
var regions = CatalogContext.Regions.AsQueryable();

var compChapters = catRelations.Where(cctr => cctr.Location == CatalogCompanyLocations.Chapter)
            .Join(catChapter, cctr => cctr.ParentID, cch => cch.ID, (cctr, cch) => new { Relation = cctr, Chapter = cch })
            .Join(catRoots, cch => cch.Chapter.CatalogRootID, cr => cr.ID, (cch, cr) => new { CatalogRoot = cr, CatalogChapter = cch.Chapter, CatalogRelation = cch.Relation })
            .Join(catCompanies, cr => cr.CatalogRelation.CompanyID, cc => cc.ID, (cr, cc) => new { Root = cr.CatalogRoot, Chapter = cr.CatalogChapter, Theme = default(CatalogTheme), Company = cc })
            .Join(regions, cc => cc.Company.RegionID, r => r.ID, (cc, r) => new { Root = cc.Root, Chapter = cc.Chapter, Theme = cc.Theme, Company = cc })
            .GroupBy(gr => new { Chapter = gr.Chapter, Name = gr.Root.Name, ID = gr.Root.ID, Icon = gr.Root.Icon, Rewrite = gr.Root.Rewrite, Sort = gr.Root.Sort })
            .Select(gr => new { Chapter = gr.Key.Chapter, ID = gr.Key.ID, Name = gr.Key.Name, Icon = gr.Key.Icon, Rewrite = gr.Key.Rewrite, Sort = gr.Key.Sort, Count = gr.Count() });

var compThemes = catRelations.Where(cctr => cctr.Location == CatalogCompanyLocations.Theme)
            .Join(catThemes, cctr => cctr.ParentID, cth => cth.ID, (cctr, cth) => new { Relation = cctr, Theme = cth })
            .Join(catChapter, cth => cth.Theme.CatalogChapterID, cch => cch.ID, (cth, cch) => new { Relation = cth.Relation, Theme = cth.Theme, Chapter = cch })
            .Join(catRoots, cch => cch.Chapter.CatalogRootID, cr => cr.ID, (cch, cr) => new { Relation = cch.Relation, Theme = cch.Theme, Chapter = cch.Chapter, Root = cr })
            .Join(catCompanies, cr => cr.Relation.CompanyID, cc => cc.ID, (cr, cc) => new { Root = cr.Root, Chapter = cr.Chapter, Theme = cr.Theme, Company = cc })
            .Join(regions, cc => cc.Company.RegionID, r => r.ID, (cc, r) => new { Root = cc.Root, Chapter = cc.Chapter, Theme = cc.Theme, Company = cc.Company })
            .GroupBy(gr => new { Chapter = gr.Chapter, Name = gr.Root.Name, ID = gr.Root.ID, Icon = gr.Root.Icon, Rewrite = gr.Root.Rewrite, Sort = gr.Root.Sort })
            .Select(gr => new { Chapter = gr.Key.Chapter, ID = gr.Key.ID, Name = gr.Key.Name, Icon = gr.Key.Icon, Rewrite = gr.Key.Rewrite, Sort = gr.Key.Sort, Count = gr.Count() });

var source = compChapters.Union(compThemes);

var chapters = source.Select(r => new { Chapter = r.Chapter, Count = r.Count }).Cast<object>().Distinct();

public static Func<DataContext, IQueryable<object>, IEnumerable<object>> filteredFunc = 
CompiledQuery.Compile<DataContext, IQueryable<object>, IEnumerable<object>>
(
      (DataContext db, IQueryable<object> q) => q.Distinct().ToList()
);

filtredChapters = filteredFunc(CatalogContext, chapters);

当我运行filteredFunc时，我得到一个错误“参数不能是序列”，这很奇怪，因为“章节”对象是IQueryable，而不是IEnumerable，为什么我得到错误？

下面的代码运行正常，但对我来说并不好。

filtredChapters = chapters.Distinct().Cast<object>().ToList();

Answer 1

您不能将编译查询与此类IEnumerable一起使用。枚举中的项目数可能会有所不同，因此查询的查询计划将根据其大小而有所不同。只需删除已编译的查询并按原样使用该函数。

linq编译查询错误“参数不能是序列”

1 个答案: