无法获得剃须刀页面的多对多导航，以从剑道网格的右表返回数据

Question

[不确定我是否说对了，但是我在net core 3.1中有一个剃须刀页面业务应用程序，其中有很多对许多连接。我现在只是在进行一个联接，并试图通过存储库调用将结果馈送到kendo网格这是示例的模型，它们是“ Notes”和“ NoteTypes”，并由“ NoteNoteTypeJoins”连接]

public class Note
{
    public int ID { get; set; }
    [Display(Name = "Short Title")]
    [Required]
    public String Title { get; set; }
    [Display(Name = "Note Content")]
    public String NoteText { get; set; }
    public int UserID { get; set; }

        //some fields left out for brevity

    public ICollection<NoteStaffJoin> NoteStaffJoins { get; set; }
    public ICollection<NoteClientJoin> NoteClientJoins { get; set; }
    public ICollection<NoteOrgJoin> NoteOrgJoins { get; set; }
    public ICollection<NoteNoteTypeJoin> NoteNoteTypeJoins { get; set; }

}
public class NoteNoteTypeJoin
{
    public int NoteNoteTypeJoinID { get; set; }
    public int NoteID { get; set; }
    public int NoteTypeID { get; set; }
    public DateTime? Saved { get; set; }
    public int? UserID { get; set; }

    public Note Note { get; set; }
    public NoteType NoteType { get; set; }


}

public class NoteType
{
    public int ID { get; set; }
    public string Type { get; set; }
    public int? ParentID { get; set; }
    public int? NoteTypeGroupID { get; set; }
    public int? DisplayOrder { get; set; }
    public int? UserID { get; set; }

    public ICollection<NoteNoteTypeJoin> NoteNoteTypeJoins { get; set; }

}
public FliveRetryContext(DbContextOptions<FliveRetryContext> options)
    : base(options)
{
    public DbSet<FliveRetry.Models.Note> Note { get; set; }
    public DbSet<FliveRetry.Models.NoteType> NoteType { get; set; }
    public DbSet<FliveRetry.Models.NoteNoteTypeJoin> NoteNoteTypeJoin { get; set; }
}

据我用ef core看到，外键等都正确定义了>>

CREATE TABLE [dbo].[NoteNoteTypeJoin] (
    [NoteNoteTypeJoinID] INT           IDENTITY (1, 1) NOT NULL,
    [NoteID]             INT           NOT NULL,
    [NoteTypeID]         INT           NOT NULL,
    [Saved]              DATETIME2 (7) NULL,
    [UserID]             INT           NULL,
    CONSTRAINT [PK_NoteNoteTypeJoin] PRIMARY KEY CLUSTERED ([NoteNoteTypeJoinID] ASC),
    CONSTRAINT [FK_NoteNoteTypeJoin_Note_NoteID] FOREIGN KEY ([NoteID]) REFERENCES [dbo].[Note] ([ID]) ON DELETE CASCADE,
    CONSTRAINT [FK_NoteNoteTypeJoin_NoteType_NoteTypeID] FOREIGN KEY ([NoteTypeID]) REFERENCES [dbo].[NoteType] ([ID]) ON DELETE CASCADE
);


GO
CREATE NONCLUSTERED INDEX [IX_NoteNoteTypeJoin_NoteID]
    ON [dbo].[NoteNoteTypeJoin]([NoteID] ASC);


GO
CREATE NONCLUSTERED INDEX [IX_NoteNoteTypeJoin_NoteTypeID]
    ON [dbo].[NoteNoteTypeJoin]([NoteTypeID] ASC);


上周，我已经在网络上尝试了每个示例，但无法正确完成。我最终使用联接表中的ID来使它工作，而该表不需要调用NoteTypes表：

public async Task<List<Note>> GetAllNotesForNoteTypeIDAsync(int notetypeid)
        {
            var noteData = await context.Note
                       .Include(n => n.NoteNoteTypeJoins)
                       .ThenInclude(t => t.NoteType)
                       .Where(i => i.NoteNoteTypeJoins.Any(x => x.NoteTypeID == notetypeid))
                       .ToListAsync();

            return noteData;
        }
我必须将此referenceloophandling选项添加到startup.cs才能使包含项完全起作用，感谢Telerik提供的信息：

services.AddRazorPages().AddNewtonsoftJson
                    (options => {
                        options.SerializerSettings.ContractResolver = new DefaultContractResolver();
                        options.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore;
                    });
这同样适用，即使包括其他表，也仅查询左表：

public async Task<List<Note>> GetAllNotesForUserAsync(int userId)
        {
            var noteData = await context.Note
                      .Include(n => n.NoteNoteTypeJoins)
                      .ThenInclude(t => t.NoteType)
                      .Where(i => i.UserID == userId)
                      .ToListAsync();

            return noteData;
        }
我想按NoteType文本而不是ID进行搜索，因为ID在不同的发行版中可能不同。这是我目前所拥有的，但是它像很多其他变体一样使页面崩溃：

public async Task<List<Note>> GetAllNotesForNoteTypeAsync(string notetype)
        {            
            var noteData = await context.Note
                       .Include(n => n.NoteNoteTypeJoins)
                       .ThenInclude(t => t.NoteType)
                       .Where(i => i.NoteNoteTypeJoins.Any(x => x.NoteType.Type.ToString() == notetype))
                       .ToListAsync();
            return noteData;
        }
此崩溃并显示以下消息：

An unhandled exception occurred while processing the request.
InvalidOperationException: The LINQ expression 'DbSet<NoteNoteTypeJoin>
.Where(n0 => EF.Property<Nullable<int>>((EntityShaperExpression: 
EntityType: Note
ValueBufferExpression: 
(ProjectionBindingExpression: EmptyProjectionMember)
IsNullable: False
), "ID") != null && EF.Property<Nullable<int>>((EntityShaperExpression: 
EntityType: Note
ValueBufferExpression: 
(ProjectionBindingExpression: EmptyProjectionMember)
IsNullable: False
), "ID") == EF.Property<Nullable<int>>(n0, "NoteID"))
.Join(
outer: DbSet<NoteType>, 
inner: n0 => EF.Property<Nullable<int>>(n0, "NoteTypeID"), 
outerKeySelector: n1 => EF.Property<Nullable<int>>(n1, "ID"), 
innerKeySelector: (o, i) => new TransparentIdentifier<NoteNoteTypeJoin, NoteType>(
Outer = o, 
Inner = i
))
.Any(n0 => n0.Inner.Type.ToString() == __notetype_0)' 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 either AsEnumerable(), AsAsyncEnumerable(), ToList(), or ToListAsync(). See https://go.microsoft.com/fwlink/?linkid=2101038 for more information.
我也没有对上一个联接的智能访问，这阻止了我在论坛上使用大量建议，因此.Where（n => n.NoteNoteTypeJoins.Type == notetype）之类的东西不可用，因为.Type在NoteNoteTypeJoins之后不可用。

这些是我需要过滤的四个多对多关系：

Note = await _context.Note
.Include(i => i.NoteOrgJoins).ThenInclude(i => i.Org)
.Include(i => i.NoteClientJoins).ThenInclude(i => i.Client)
.Include(i => i.NoteStaffJoins).ThenInclude(i => i.Staff)
.Include(i => i.NoteNoteTypeJoins).ThenInclude(i => i.NoteType)

[如果有人可以建议一个有效的导航电话而不是加入，至少可以使我摆脱笔记类型电话的麻烦，我会很高兴，如果您可以向我展示如何添加其他电话，那会更好。我仍在学习C＃和剃须刀，因此它可能不在通话本身内，但我尝试遵循标准设置。 

感谢所有人

[不确定我是否说对了，但是我在net core 3.1中有一个剃须刀页面业务应用程序，其中有很多对许多连接。我现在只是在进行一个联接，并试图将结果提供给...

Answer 1

我也没有对上一个联接的智能访问，这阻止了我在论坛上使用大量建议，因此.Where（n => n.NoteNoteTypeJoins.Type == notetype）之类的东西不可用，因为.Type在NoteNoteTypeJoins之后不可用。