EF .NET Core 5 异常中的 LINQ 表达式 'OUTER APPLY Projection Mapping

如何解决EF .NET Core 5 异常中的 LINQ 表达式 'OUTER APPLY Projection Mapping

从 .NET Core 2.x 迁移到 .NET Core 5.0 后，我们面临这个问题。

错误：（添加为代码以提高可读性）

 The LINQ expression 'OUTER APPLY Projection Mapping:
(
    SELECT e0.Id,e0.FirstName,e0.MiddleName,e0.LastName
    FROM Employees AS e0
    WHERE (((e0.Status != 4) && EXISTS (
        Projection Mapping:
        SELECT 1
        FROM FunctionRoles AS f0
        WHERE t.Id == f0.SchoolId)) && (e0.FunctionRoleId == (Projection Mapping:
            EmptyProjectionMember -> 0
        SELECT TOP(1) f1.Id
        FROM FunctionRoles AS f1
        WHERE (t.Id == f1.SchoolId) && (f1.Name == 'Manager')))) && (t.Id == e0.SchoolId)
) AS t0' Could not be translated. Either rewrite the query in a form that can be translated,or switch to client evaluation explicitly by inserting a call to 'AsEnumerable','AsAsyncEnumerable','ToList',or 'ToListAsync'. 
See https://go.microsoft.com/fwlink/?linkid=2101038 for more information.

代码部分：

using (var dbContext = _contextProvider.CreateContext())
        {
            var school = dbContext.Set<Domain.Model.School>()
                .Where(s => s.Id == schoolId)
                .Select(s => new SchoolSummaryDto
                {
                    

                    //... Some other properties

                    DocumentTemplates = s.DocumentTemplates != null ? s.DocumentTemplates.Select(a => new DocumentTemplateDto
                    { Id = a.Id,Description = a.Description,SchoolId = a.SchoolId,FileName = a.FileName,DocumentTemplateTypeId = a.DocumentTemplateTypeId }).ToList() : new List<DocumentTemplateDto>(),// This below chunk is causing problem.
                    Signers = s.Employees != null ? s.Employees.AsEnumerable().Where(
                        e => e.Status != PersistentStatusEnum.Removed &&
                        e.FunctionRoleId == s.FunctionRoles.AsEnumerable().Single(
                        b => b.Name == FunctionRolesEnum.Manager.ToString()).Id).AsEnumerable().Select(
                        a => new NameValueType { Id = a.Id,Name = string.Format("{0} {1} {2}",a.FirstName,a.MiddleName,a.LastName) }).ToList() : new List<NameValueType>(),// .. Error chunk ends here

                    ContactPerson = s.ContactPerson,Email = s.Email,PhoneNumber = s.PhoneNumber,SchoolId = s.Id,SchoolName = s.Name,Website = s.Website,IsEnabled = s.IsEnabled,IsRegistered = s.IsRegistered
                }).FirstOrDefault();

        }

我的尝试： 根据这些 Microsoft 链接 Breaking Changes 和 Queryable projection not supported，我尝试并应用了相应的更改 AsEnumerable()，如上所示。

现在需要进行哪些更改？

图书馆和环境：

1. 数据库 => MysqL
2. 库 => Pomelo.EntityFrameworkCore.MysqL (5.0.0-alpha.2) Nuget Link

我感觉要么是这个 MysqL 库导致了问题，要么是 EF Core 5 的重大更改。

编辑 1：

public class FunctionRole:AuditableEntity
{
    public string Name { get; set; }
    public string Description { get; set; }
    public Guid SchoolId { get; set; }
    public virtual School School { get; set; }
}

public class School:AuditableEntity
{
    public bool IsRegistered { get; set; }
    public bool IsEnabled { get; set; }
    public string Name { get; set; }
    public string Email { get; set; }
    public string Website { get; set; }
    public string PhoneNumber { get; set; }
    public string ContactPerson { get; set; }
    public string ActivationCode { get; set; }

    public virtual ICollection<FunctionRole> FunctionRoles { get; set; }

    public virtual ICollection<DocumentTemplate> DocumentTemplates { get; set; }
    

}