相关疑难解决方法(0)

我有以下Entity Framework Core 3.0：

var units = await context.Units
  .SelectMany(y => y.UnitsI18N)
  .OrderBy(y => y.Name)
  .GroupBy(y => y.LanguageCode)
  .ToDictionaryAsync(y => y.Key, y => y.Select(z => z.Name));

我得到以下错误：

Client side GroupBy is not supported.

如果未在客户端上运行查询，为什么会出现此错误？

要在客户端或客户端的一部分上运行查询，我将执行以下操作：

var units = context.Units
  .SelectMany(y => y.UnitsI18N)
  .OrderBy(y => y.Name)
  .AsEnumerable()
  .GroupBy(y => y.LanguageCode)
  .ToDictionary(y => y.Key, y => y.Select(z => z.Name));

现在可以了...

在 EF Core 2.2 中，我有：

      var data = await _ArticleTranslationRepository.DbSet
        .Include(arttrans => arttrans.Article)
        .ThenInclude(art => art.Category)
        .Where(trans => trans.Article != null && trans.Article.Category != null && trans.Article.Category.Id == categoryId.Value)
        .GroupBy(trans => trans.ArticleId)
        .Select(g => new { ArticleId = g.Key, TransInPreferredLang = g.OrderByDescending(trans => trans.LanguageId == lang).ThenByDescending(trans => trans.LanguageId == defaultSiteLanguage).ThenBy(trans => trans.LanguageId).FirstOrDefault() })
        .Select(at => at.TransInPreferredLang)
        .OrderBy(at => at.Article.SortIndex)
        .ToListAsync();

现在使用 EF Core 3.0 我不得不写：

      var data = _ArticleTranslationRepository.DbSet
  .Include(arttrans => arttrans.Article)
  .ThenInclude(art => art.Category)
  .Where(trans => trans.Article != null …