无法从 kendo 网格的右手 table 获取多对多导航到 return 数据的剃刀页面

Question

不确定我说的对不对，但我在 net core 3.1 中有一个 razor pages 业务应用程序，有很多多对多连接。我目前正在处理一个连接并尝试通过存储库调用将结果提供给 kendo 网格以下是示例的模型，由 "NoteNoteTypeJoins"

加入 "Notes" 和 "NoteTypes"


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 ef core 所见，外键等都已正确定义

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);

上周我已经尝试了网络上的所有示例，但无法正确使用。我最终使用连接 table 中的 ID 使其工作，不需要调用 NoteTypes table:

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;
        }

我必须将此引用循环处理选项添加到 startup.cs 才能使包含工作，感谢 Telerik 提供的信息：

services.AddRazorPages().AddNewtonsoftJson
                    (options => {
                        options.SerializerSettings.ContractResolver = new DefaultContractResolver();
                        options.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore;
                    });

这同样有效，只查询左手 table，即使包括其他人：

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，因为不同版本的 ID 可能不同。这就是我目前所拥有的，但它使页面崩溃，就像许多其他变体一样：

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.

我也没有对最后加入的智能感知访问权限，这阻止了我在论坛上使用很多建议，所以像 .Where(n => n.NoteNoteTypeJoins.Type == notetype)) 这样的东西'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调用而不是加入，那至少可以让我摆脱笔记类型调用的麻烦，我会很兴奋，如果你能告诉我如何添加其他调用好吧，那会更好。我仍在学习 C# 和剃刀，所以它可能是调用本身之外的东西，但我试图坚持标准设置。

感谢大家

Answer 1

I also don't have intellisense access to the last join, which is stopping me using a lot of suggestions on forums so something like .Where(n => n.NoteNoteTypeJoins.Type == notetype)) isn't available because .Type isn't available after NoteNoteTypeJoins.

原因是 EF Core 3 中禁用了隐式客户端计算。

参考：

https://docs.microsoft.com/en-us/ef/core/what-is-new/ef-core-3.0/breaking-changes#linq-queries-are-no-longer-evaluated-on-the-client

您可以像下面这样更改您的代码：

var noteData = await _context.Note
                   .Include(n => n.NoteNoteTypeJoins)
                   .ThenInclude(t => t.NoteType)                                    
                   .ToListAsync();

var d = noteData.Where(i => i.NoteNoteTypeJoins.Any(x => x.NoteType.Type.ToString() == notetype))
                .ToList();

另一种方式是你的NoteTypeclass中的Type属性是string.No的类型需要使用ToString()方法：

var noteData = await _context.Note
                   .Include(n => n.NoteNoteTypeJoins)
                   .ThenInclude(t => t.NoteType)
                   .Where(i => i.NoteNoteTypeJoins.Any(x => x.NoteType.Type == notetype))
                   .ToListAsync();

无法从 kendo 网格的右手 table 获取多对多导航到 return 数据的剃刀页面

Cant get a razor page many to many navigation to return data from the right hand table for a kendo grid

c#

entity-framework

razor

kendo-grid

asp.net-core