LINQ erreur de requête compilé « parameteres ne peut pas être des séquences »

Question

J'ai le code ci-dessous:

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); 

Je reçois une erreur « parameteres ne peuvent pas être des séquences » quand je lance filteredFunc, ce qui est étrange, parce que L'objet "chapters" est IQueryable, pas IEnumerable, alors pourquoi ai-je l'erreur?

Le code ci-dessous fonctionne bien, mais ce n'est pas bon pour moi.

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

Answer 1

Vous ne pouvez pas utiliser les requêtes compilées avec un IEnumerable comme ceci. Le nombre d'éléments dans l'énumération peut varier et le plan de requête de la requête variera en fonction de sa taille. Supprimez simplement la requête compilée et utilisez la fonction telle quelle.