ASP.NET Core 3.1-EF Core无法翻译GroupBy和Join

Question

我最近更新了我的Web应用程序，很遗憾，我所有最复杂的请求都不再适用。我看到很多人都有这个问题，但是我不太了解如何解决。我知道其他帖子也谈到了这一点，但我看不出如何使它适应我的要求。我有两种有问题的请求：

第一个问题（已解决）：

 //error in this part "GroupBy(i => i.CodeMemo).Where(g => g.Count() == 1)"
var MemoMonde = await _context.MemoEmploye.GroupBy(i => i.CodeMemo).Where(g => g.Count() == 1)
                .Select(g => g.FirstOrDefault()).Select(emp => new
                {

                    emp.CodeMemo,
                    emp.Lu,
                    emp.Actif,
                    Memo = new
                    {
                        emp.CodeMemoNavigation.Titre,
                        emp.CodeMemoNavigation.Contenu,
                        emp.CodeMemoNavigation.DateEcheance,
                        emp.CodeMemoNavigation.Urgent,
                        emp.CodeMemoNavigation.CodeEmploye,
                        emp.CodeMemoNavigation.CodeSociete,
                        emp.CodeMemoNavigation.DateCreation,
                        emp.CodeMemoNavigation.ToutLeMonde,
                        emp.CodeMemoNavigation.Supprime,
                        emp.CodeMemo



                    },
                    destinataireE = new
                    {
                        emp.CodeEmployeNavigation.Nom,
                        emp.CodeEmployeNavigation.Prenom,
                        emp.CodeEmployeNavigation.CodeEmploye,
                        emp.CodeEmployeNavigation.Identifiant
                    },
                    employe = emp.CodeMemoNavigation.CodeEmploye != null
                        ? _context.Employe.Select(soc => new { soc.Nom, soc.Prenom, soc.Identifiant, soc.CodeEmploye }).FirstOrDefault(code =>
                            code.CodeEmploye == emp.CodeMemoNavigation.CodeEmploye)
                        : null,

                    societe = emp.CodeMemoNavigation.CodeSociete != null
                        ? _context.Societe.Select(soc => new { soc.Nom, soc.CodeSociete }).FirstOrDefault(code =>
                              code.CodeSociete == emp.CodeMemoNavigation.CodeSociete)
                        : null
                    ,
                    photo = _context.MemoFichier.Select(file => new
                    {
                        file.CodeMemo,
                        file.CodeFichier,
                        file.CodeFichierNavigation.Chemin,
                        file.CodeFichierNavigation.Nom
                    }).Where(fi => fi.CodeMemo == emp.CodeMemo).ToList()
                }).Where(t =>
                    t.destinataireE.CodeEmploye == codeEmploye && !t.Memo.Supprime && t.Actif)
                .OrderByDescending(r => r.Memo.DateCreation).ToListAsync();

在没有GroupBy的情况下获得ef核心3中表的非唯一值计数的解决方案：

var memoSANS = _context.MemoEmploye.Where(x => x.CodeEmploye != codeEmploye).ToList();
var memoSANS1 = memoSANS.Select(x => x.CodeMemo).ToList();
var memoAVEC = _context.MemoEmploye.Where(x => x.CodeEmploye == codeEmploye && !memoSANS1.Contains(x.CodeMemo)).ToList();
var memoAVEC1 = memoAVEC.Select(x => x.CodeMemo).ToList();
and && memoAVEC1.Contains(t.CodeMemo) to the big request

第二个问题：

var MemoEmp = await _context.MemoEmploye.Select(mr => new
            {
                mr.CodeEmployeNavigation.Identifiant,
                mr.CodeMemo,
                mr.CodeEmployeNavigation.Nom,
                mr.CodeEmployeNavigation.Prenom,
                mr.Lu,
                mr.Actif,
                mr.CodeEmploye,
                Memo = new
                {
                    mr.CodeMemoNavigation.Titre,
                    mr.CodeMemoNavigation.Contenu,
                    mr.CodeMemoNavigation.DateEcheance,
                    mr.CodeMemoNavigation.Urgent,
                    mr.CodeMemoNavigation.CodeEmploye,
                    mr.CodeMemoNavigation.CodeSociete,
                    mr.CodeMemoNavigation.DateCreation,
                    mr.CodeMemoNavigation.ToutLeMonde,
                    mr.CodeMemoNavigation.Supprime,

                    mr.CodeMemoNavigation.CodeMemo
                },
                destinataireE = mr.CodeMemoNavigation.MemoEmploye.Select(a =>
                    new
                    {
                        a.CodeEmployeNavigation.Nom,
                        a.CodeEmployeNavigation.Prenom,
                        a.CodeEmployeNavigation.Identifiant,
                        a.CodeEmployeNavigation.CodeRole,
                        a.CodeEmployeNavigation.CodeEmploye
                    }).ToList(),
                employe = new
                {
                    mr.CodeMemoNavigation.CodeEmployeNavigation.Nom,
                    mr.CodeMemoNavigation.CodeEmployeNavigation.Prenom,
                    mr.CodeMemoNavigation.CodeEmployeNavigation.Identifiant
                },
                societe = mr.CodeMemoNavigation.CodeSociete != null ? _context.Societe.Select(soc => new { soc.Nom, soc.CodeSociete }).FirstOrDefault(code => code.CodeSociete == mr.CodeMemoNavigation.CodeSociete): null
                ,
                photo = _context.MemoFichier.Select(file => new
                {
                    file.CodeMemo,
                    file.CodeFichier,
                    file.CodeFichierNavigation.Chemin,
                    file.CodeFichierNavigation.Nom
                }).Where(fi => fi.CodeMemo == mr.CodeMemo).ToList()
            }).Where(me => me.CodeEmploye == codeEmploye && !me.Memo.Supprime && me.Actif && !MemoMonde.Select(r => r.Memo.CodeMemo).DefaultIfEmpty().Contains(me.Memo.CodeMemo) && !Archi.Select(r => r.Memo.CodeMemo).ToList().Contains(me.Memo.CodeMemo) && me.destinataireE.Count() != 1).ToListAsync();
//error in this part : "!Archi.Select(r => r.Memo.CodeMemo).ToList().Contains(me.Memo.CodeMemo)" & "!MemoMonde.Select(r => r.Memo.CodeMemo).DefaultIfEmpty().Contains(me.Memo.CodeMemo)"
//the error comes from me.destinataireE.Count() != 1 we can't specify condition about a nested request

已解决：错误来自于我。destinataireE.Count（）！= 1我们无法指定有关嵌套请求的条件

我在那里呆了几个小时却没有结果，我急切地寻求帮助