Question

我正在尝试实现以多对多关系更新我的实体的函数 - remove or insert。我需要模型 - 用户可以在多个会议中，会议可以有多个用户我正在使用EntityFramework Core 2.0.1。因为我发现EF核心2. [x]还不支持多对多的连接，所以我创建了一个自定义连接表。

问题

当我想插入新实体时出现问题 - Attach（在SaveChanges()之后）没有将任何更改传播到数据库中，我没有收到任何错误。删除实体正常工作。我使用了关于从source进行更新的想法。使用了很好的扩展名Except来获取已删除的插入的扩展名AddRange。

<小时/> 我在一个单独的线程上找到了一个解决方案 - 右here。不幸的是，结果不成功，然后我获得了有关IdentityUserCustom表（AspNetUsers表）中主键冲突的信息 - 使用List方法创建了UserConference

public class IdentityUserCustom : IdentityUser
{
    public string ColorProfile { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }

    public virtual ICollection<UserConference> UsersConferences { get; set; }
    public virtual ICollection<IdentityUserRole<string>> Roles { get; } = new List<IdentityUserRole<string>>();

}

这导致我认为我是在尝试插入现有记录，实际上是不是我创建UserConference列表的问题？此解决方案可能也存在类似的问题。

<小时/> 为了清晰起见，我将缩短属性和其余代码。

用户实体 扩展了IdentityUser类

public class Conference
{
    public int ConferenceId { get; set; }
    public virtual ICollection<UserConference> UsersConferences { get; set; }
}

会议实体

public class UserConference
{
    public string UserId { get; set; }
    public virtual IdentityUserCustom User { get; set; }

    public int ConferenceId { get; set; }
    public virtual Conference Conference { get; set; }
}

加入表格

[HttpPut]
public async Task<object> UpdateConference([FromBody]ConferenceViewModel model)
{
    try
    {
        using (_unitOfWork)
        {
            //find conference
            var conference =
                await _unitOfWork.GetDbContext().Conferences.Include(p => p.UsersConferences)
                    .FirstOrDefaultAsync(p => p.ConferenceId == model.ConferenceId);

            if (conference != null)
            {
                var usersConferences = new List<UserConference>();

                //get UserConference from model and create collection
                if (model.UsersConferences.Any())
                {
                    foreach (var userModel in model.UsersConferences)
                    {
                        //find existing user
                        var user = await _userManager.FindByNameAsync(userModel.UserName);
                        if (user != null)
                        {
                            //make relationship
                            usersConferences.Add(new UserConference { Conference = conference, ConferenceId = model.ConferenceId, User = user, UserId = user.Id });
                        }
                    }

                }

                //get deleted users 
                var deletedUsers =
                    conference.UsersConferences.Except(usersConferences, p => (p.UserId, p.ConferenceId)).ToList();

                //get newly added users
                var addedUsers = usersConferences.Except(conference.UsersConferences,
                    p => (p.UserId, p.ConferenceId)).ToList();

                //remove deleted users
                foreach (var deletedUsr in deletedUsers)
                {
                    conference.UsersConferences.Remove(deletedUsr);
                }

                //add new users
                foreach (var addUsr in addedUsers)
                {
                    //check if detached
                    if (_unitOfWork.GetDbContext().Entry(addUsr).State == EntityState.Detached)
                        _unitOfWork.GetDbContext().UsersConferences.Attach(addUsr);

                    //add to existing conference
                    conference.UsersConferences.Add(addUsr);
                }

                //commit - SaveChanges()
                _unitOfWork.Commit();

            }

            //just for any response
            return "OK";
        }
    }
    catch (Exception e)
    {
        //log it
    }
}

WebApi更新方法

  mail = Mail.new

  # ..........
  # it returns html
  mail.body = ERB.new(File.read(File.expand_path("templates/email/main.html"))).result(binding)

  # mail.body does contain html now
  # ......
  mail.attachments["something.pdf"] = File.binread(.....)

EntityFramework Core 2.0.1多对多，为什么更新不起作用？

问题

0 个答案: