Question

我有一个名为 ClubApplicationUser 的模型，它是 Club 和 ApplicationUser 之间的桥梁，该模型是 Identity User 的扩展模型。 strong>模型：

public class ClubApplicationUser { public Guid ClubID { get; set; } public Club Club { get; set; } public string Id { get; set; } public ApplicationUser ApplicationUser { get; set; } public DateTime DateCreated { get; set; } public string CreatedBy { get; set; } public DateTime LastDateModified { get; set; } public string LastModifiedBy { get; set; } public DateTime? DateDeleted { get; set; } public string DeletedBy { get; set; } public bool IsDeleted { get; set; } [Timestamp] public byte[] RowVersion { get; set; } [ForeignKey("CreatedBy")] public ApplicationUser ClubApplicationCreatedUser { get; set; } [ForeignKey("LastModifiedBy")] public ApplicationUser ClubApplicationLastModifiedUser { get; set; } }

在ApplicationDBContext-OnModelCreating中，我们定义了关系：

builder.Entity<ClubApplicationUser>() .HasKey(bc => new { bc.ClubID, bc.Id }); builder.Entity<ClubApplicationUser>() .HasOne(bc => bc.Club) .WithMany(b => b.ClubApplicationUsers) .HasForeignKey(bc => bc.ClubID); builder.Entity<ClubApplicationUser>() .HasOne(bc => bc.ApplicationUser) .WithMany(c => c.ClubApplicationUsers) .HasForeignKey(bc => bc.Id);

我们有一个问题，无法更新，并且出现错误：

InvalidOperationException：实体类型上的属性'ClubID' 'ClubApplicationUser'是密钥的一部分，因此无法进行修改或标记为已修改。用以下方法更改现有实体的主体标识外键首先删除依赖项并调用然后，“ SaveChanges”将依赖项与新的主体相关联。

这是AssignClub.cs：

public class AssignClubUserModel : ClubNamePageModel { private readonly AthlosifyWebArchery.Data.ApplicationDbContext _context; public AssignClubUserModel(AthlosifyWebArchery.Data.ApplicationDbContext context) { _context = context; } public class AssignClubUserViewModel<ApplicationUser> { public string FirstName { get; set; } public string LastName { get; set; } public string UserName { get; set; } public Guid SelectedClubID { get; set; } public byte[] RowVersion { get; set; } } [BindProperty] public AssignClubUserViewModel<ApplicationUser> AssignClubUser { get; set; } public SelectList ClubNameSL { get; set; } public async Task<IActionResult> OnGetAsync(Guid? id) { if (id == null) return NotFound(); var user = await _context.Users .Include(u => u.ClubApplicationUsers) .Where(t => t.Id == id.ToString()) .Select(t => new AssignClubUserViewModel<ApplicationUser> { FirstName = t.FirstName, LastName = t.LastName, UserName = t.UserName, SelectedClubID = t.ClubApplicationUsers.ElementAt(0).ClubID, RowVersion = t.RowVersion }).SingleAsync(); AssignClubUser = user; // Use strongly typed data rather than ViewData. ClubNameSL = new SelectList(_context.Club, "ClubID", "Name"); //PopulateClubsDropDownList(_context); return Page(); } public async Task<IActionResult> OnPostAsync(Guid id) { if (!ModelState.IsValid) { return Page(); } // 1st approach: // Modify the bridge model directly var clubApplicationUserToUpdate = await _context.ClubApplicationUser .FirstOrDefaultAsync(m => m.Id == id.ToString()); if (clubApplicationUserToUpdate == null) { return await HandleDeletedUser(); } _context.Entry(clubApplicationUserToUpdate) .Property("RowVersion").OriginalValue = AssignClubUser.RowVersion; _context.Entry(clubApplicationUserToUpdate) .Property("ClubID").OriginalValue = AssignClubUser.SelectedClubID; await _context.SaveChangesAsync(); // 2nd approach: // Soft -Delete and Add // Did the soft-deleting and managed to add a new one BUT then die the roll back (adding the old one) // Result: Violation of PRIMARY KEY constraint 'PK_ClubApplicationUser'. // Cannot insert duplicate key in object // Due to duplicate key /*var clubApplicatonUserToRemove = await _context.ClubApplicationUser .FirstOrDefaultAsync(m => m.Id == id.ToString()); ClubApplicationUser clubApplicatonUserToAdd = new ClubApplicationUser(); clubApplicatonUserToAdd.Id = id.ToString(); clubApplicatonUserToAdd.ClubID = AssignClubUser.SelectedClubID; //_context.Entry(clubApplicatonUserToRemove) // .Property("RowVersion").OriginalValue = User.RowVersion; if (clubApplicatonUserToRemove != null) { _context.ClubApplicationUser.Remove(clubApplicatonUserToRemove); await _context.SaveChangesAsync(); _context.ClubApplicationUser.Add(clubApplicatonUserToAdd); await _context.SaveChangesAsync(); }*/ return Page(); } private async Task<IActionResult> HandleDeletedUser() { //ClubA deletedClubApplicationUser = new ApplicationUser(); //ModelState.AddModelError(string.Empty, // "Unable to save. The user was deleted by another user."); //ClubNameSL = new SelectList(_context.Roles, "Id", "Name", User.UserRoles.ElementAt(0).RoleId); return Page(); } private async Task setDbErrorMessage(ApplicationUser dbValues, ApplicationUser clientValues, ApplicationDbContext context) { if (dbValues.FirstName != clientValues.FirstName) { ModelState.AddModelError("User.FirstName", $"Current value: {dbValues.FirstName}"); } if (dbValues.LastName != clientValues.LastName) { ModelState.AddModelError("User.LastName", $"Current value: {dbValues.LastName}"); } if (dbValues.Email != clientValues.Email) { ModelState.AddModelError("User.Email", $"Current value: {dbValues.Email}"); } ModelState.AddModelError(string.Empty, "The record you attempted to edit " + "was modified by another user after you. The " + "edit operation was canceled and the current values in the database " + "have been displayed. If you still want to edit this record, click " + "the Save button again."); } }

...和AssignClub.cshtml：

@page @model AthlosifyWebArchery.Pages.Administrators.Users.AssignClubUserModel @{ ViewData["Title"] = "Assign Club"; } <h2>Assign Club</h2> <h4>User</h4> <hr /> <div class="row"> <div class="col-md-4"> <form method="post"> <div asp-validation-summary="ModelOnly" class="text-danger"></div> <div class="form-group"> <label asp-for="AssignClubUser.FirstName" class="control-label"> </label> <input asp-for="AssignClubUser.FirstName" disabled class="form- control" /> </div> <div class="form-group"> <label asp-for="AssignClubUser.LastName" class="control-label"> </label> <input asp-for="AssignClubUser.LastName" disabled class="form-control" /> </div> <div class="form-group"> <label asp-for="AssignClubUser.UserName" class="control-label"> </label> <input asp-for="AssignClubUser.UserName" disabled class="form-control" /> </div> <div class="form-group"> <label class="control-label">Club</label> <select asp-for="AssignClubUser.SelectedClubID" class="form-control" asp-items="@Model.ClubNameSL"> <option value="">-- Select Club --</option> </select> <span asp-validation-for="AssignClubUser.SelectedClubID" class="text-danger"></span> </div> <div class="form-group"> <input type="submit" value="Save" class="btn btn-default" /> </div> </form> </div> </div> <div> <a asp-page="./Index">Back to List</a> </div> @section Scripts { @{await Html.RenderPartialAsync("_ValidationScriptsPartial");} }

环境： .Net Core 2.2 剃刀页面

更新-1：

如果我们直接通过以下操作在数据库上进行更新：

UPDATE [ClubApplicationUser] SET ClubID = '85715C34-AFC6-4498-DA7F-08D66CAE7A01' WHERE Id = 'ecbd27b4-03bc-4b99-82b3-76d9aa5bc7fc'

我们可以更新此问题。因此，它看起来像.Net核心模型中的约束。

Answer 1

我认为最好的解决方案是您需要删除并插入而不是更新，尽管实际上给您的ClubApplicationUser可能意味着对IsDeleted字段进行更新，而不是实际执行Delete。

如果您以自己的域的逻辑来考虑，我认为用户通常不会从一个俱乐部的成员变成另一个俱乐部的成员，而是会离开（删除）一个俱乐部并加入（插入）另一个俱乐部。

尽管我可以提出另一个可以进行更新的域，所以我认为这不是一个很好的通用论点。

以下代码显示问题的简化版本。您可以看到测试允许插入和删除，但由于更新失败

public class Club
{
    public int Id { get; set; }
    public string Name { get; set; }

    public IList<ClubUser> Users { get; set; }
}

public class User
{
    public int Id { get; set; }

    public string Name { get; set; }

    public IList<ClubUser> Clubs { get; set; }
}

public class ClubUser
{
    public int ClubID { get; set; }

    public Club Club { get; set; }

    public int Id { get; set; }

    public User User { get; set; }

    public string Extra { get; set; }
}

public class ApplicationDbContext : Microsoft.EntityFrameworkCore.DbContext
{
    public DbSet<User> Users { get; set; }
    public DbSet<Club> Clubs { get; set; }
    public DbSet<ClubUser> ClubUsers { get; set; }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder.UseSqlServer(@"Server=.;Database=Spike;Trusted_Connection=True;");
    }

    protected override void OnModelCreating(Microsoft.EntityFrameworkCore.ModelBuilder builder)
    {
        builder.Entity<Club>()
            .HasKey(c => c.Id );

        builder.Entity<User>()
            .HasKey(c => c.Id );

        builder.Entity<ClubUser>()
            .HasKey(cu => new { cu.ClubID, cu.Id });

        builder.Entity<ClubUser>()
                .HasOne<Club>(cu => cu.Club)
                .WithMany(u => u.Users)
                .HasForeignKey(bc => bc.ClubID);

        builder.Entity<ClubUser>()
                .HasOne<User>(cu => cu.User)
                .WithMany(c => c.Clubs)
                .HasForeignKey(cu => cu.Id);

    }
}

[TestClass]
public class ManyToMany
{
    [TestMethod]
    public void DeleteAndInsert()
    {
        var context = new ApplicationDbContext();

        var clubusers = context.ClubUsers;
        var clubs = context.Clubs;
        var users = context.Users;

        var original = clubusers.First();
        clubusers.Remove(original);

        var newClubUser = new ClubUser
        {
            Club = clubs.Last(),
            User = users.First(),
            Extra = "Another"
        };

        clubusers.Add(newClubUser);

        context.SaveChanges();
    }

    [TestMethod]
    public void Update()
    {
        var context = new ApplicationDbContext();

        var clubusers = context.ClubUsers;
        var clubs = context.Clubs;
        var users = context.Users;

        var update = clubusers.First();
        update.Club = clubs.Last();
        update.Extra = "Changed";

        Assert.ThrowsException<InvalidOperationException>( () =>  context.SaveChanges());
    }
}

要初始化测试数据库：

ALTER TABLE [dbo].[ClubUsers] DROP CONSTRAINT [FK_ClubUser_User]
GO

ALTER TABLE [dbo].[ClubUsers] DROP CONSTRAINT [FK_ClubUser_Club]
GO

DROP TABLE [dbo].[ClubUsers]
GO

DROP TABLE [dbo].[Clubs]
GO

DROP TABLE [dbo].[Users]
GO

CREATE TABLE [dbo].[Clubs](
    [Id] [int] IDENTITY(1,1) NOT NULL,
    [Name] [varchar](50) NOT NULL,
 CONSTRAINT [PK_Club] PRIMARY KEY CLUSTERED 
(
    [Id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO

CREATE TABLE [dbo].[Users](
    [Id] [int] IDENTITY(1,1) NOT NULL,
    [Name] [varchar](50) NOT NULL,
 CONSTRAINT [PK_User] PRIMARY KEY CLUSTERED 
(
    [Id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO

CREATE TABLE [dbo].[ClubUsers](
    [ClubId] [int] NOT NULL,
    [Id] [int] NOT NULL,
    [Extra] [varchar](50) NOT NULL,
 CONSTRAINT [PK_ClubUser] PRIMARY KEY CLUSTERED 
(
    [ClubId] ASC,
    [Id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO

ALTER TABLE [dbo].[ClubUsers]  WITH CHECK ADD  CONSTRAINT [FK_ClubUser_Club] FOREIGN KEY([ClubId])
REFERENCES [dbo].[Clubs] ([Id])
GO

ALTER TABLE [dbo].[ClubUsers] CHECK CONSTRAINT [FK_ClubUser_Club]
GO

ALTER TABLE [dbo].[ClubUsers]  WITH CHECK ADD  CONSTRAINT [FK_ClubUser_User] FOREIGN KEY([Id])
REFERENCES [dbo].[Users] ([Id])
GO

ALTER TABLE [dbo].[ClubUsers] CHECK CONSTRAINT [FK_ClubUser_User]
GO

INSERT Clubs(Name)
VALUES ('GlenEagles');

INSERT Clubs(Name)
VALUES ('StAndrews');

INSERT Clubs(Name)
VALUES ('Wentworth');

INSERT dbo.[Users](Name)
VALUES ('Pete');

INSERT dbo.[Users](Name)
VALUES ('Dave');

INSERT ClubUsers(ClubId, Id, Extra)
VALUES (1,1, 'Hello');

Answer 2

*无效，请参见评论*

我的第三个选择是最快实现的，但是我不确定所有的含义。

如果将OnModelCreating更改为设置索引而不是键

即

        builder.Entity<ClubUser>()
            .HasKey(cu => new { cu.ClubID, cu.Id });

成为

        builder.Entity<ClubUser>()
            .HasIndex(cu => new { cu.ClubID, cu.Id });

该更新现在可以正常工作，但是您在ClubUser上没有密钥，这可能会导致其他问题。

Answer 3

关于：

InvalidOperationException：实体类型上的属性'ClubID' “ ClubApplicationUser”是密钥的一部分...

ClubApplicationUsers表中的

PrimaryKey既是ClubID又是ID。您不能仅通过ID更改现有记录。

例如：

var clubApplicationUserToUpdate = await _context.ClubApplicationUser
    .FirstOrDefaultAsync(m => m.Id == id.ToString());

必须是这样的：

var clubApplicationUserToUpdate = await _context.ClubApplicationUser
    .FirstOrDefaultAsync(m => m.Id == id.ToString() && m.ClubID == AssignClubUser.SelectedClubID.ToString());

或者：

var clubApplicationUsersToUpdate = await _context.ClubApplicationUser
        .Where(m => m.Id == id.ToString()).ToList();

关于：

第二种方法：
  ...
  结果：违反了PRIMARY KEY约束'PK_ClubApplicationUser'。

我将举例说明：

Clubs: 1, 2, 3
ApplicationUsers: A, B, C
ClubApplicationUser: A1, A2

尝试删除A1，然后添加A2-表示A2已经存在。

解决方案更接近第二种方法：

public async Task<IActionResult> OnPostAsync(Guid id)
{
    if (!this.ModelState.IsValid)
    {
        return Page();
    }

    //delete all club memberships and add new one
    var clubApplicatonUsersToRemove = await _context.ClubApplicationUser
        .Where(m => m.Id == id.ToString()).ToList();

    foreach (var clubApplicatonUser in clubApplicatonUsersToRemove)
    {
        _context.ClubApplicationUser.Remove(clubApplicatonUser);
    }

    _context.ClubApplicationUser.Add(new ClubApplicationUser()
    {
        Id = id.ToString(),
        ClubID = AssignClubUser.SelectedClubID
    });

    await _context.SaveChangesAsync();

    return Page();
}

如果您不想删除任何内容，而只需添加新记录：

public async Task<IActionResult> OnPostAsync(Guid id)
{
    if (!this.ModelState.IsValid)
    {
        return Page();
    }

    // dont delete, just add new one
    var clubApplicatonUserExists = await _context.ClubApplicationUser
        .Where(m => m.Id == id.ToString() && m.ClubID == AssignClubUser.SelectedClubID).FirstOrDefaultAsync();


    if (clubApplicatonUserExists == null)
    {
        _context.ClubApplicationUser.Add(new ClubApplicationUser()
        {
            Id = id.ToString(),
            ClubID = AssignClubUser.SelectedClubID
        });

        await _context.SaveChangesAsync();
    }

    return Page();
}

Answer 4

如果您对数据库架构有控制权，另一种解决方案是向链接表添加一个多余的键。

然后，如果您需要更新俱乐部或用户，则无需更改实体唯一标识符，因此将被允许。

需要帮助来更新模型

4 个答案: