C# Asp.net C应用程序用户的多对多关系

诚然，我在深水区工作，尽管我一直在浏览许多“类似”的帖子，但我似乎无法理解这一点

我正试图与公司模型和应用程序用户建立联系。 该公司持有许多非盟，非盟可以持有许多公司。虽然当我创建一家公司并从我选中的selectList中选择不同的用户时，确实传递了AU-ID

警告：我只是一个新手，我很难弄清楚遵循指南和其他什么，所以可能会有明显的错误

模范公司：

---

通过正确配置的类，您应该能够执行类似的操作：

var userList = new List<ApplicationUser>();
foreach (string i in model.SelectedApplicationUserIds)
{
    userList.Add(new ApplicationUser {Id = i});
}

var newCompany = new Company
{
    Address = model.Address;
    BillingEmail = model.BillingEmail;
    City = model.City;
    // etc. 
    Users = userList
};

int response = await context.SaveChangesAsync();

---

EF将自动进行联动。注意：您不需要使用UserManager来检索用户-它可以从context.users获得。

您的公司模型具有公共列表UserId-这是字符串的集合。摆脱它，使用你的ApplicationUsers集合。请看这个类似的问题：谢谢你的评论。我已经更新了代码，但是收到一个验证错误。。我不确定这是否是你的意思。这是你建议的方法吗？`虽然链接是相似的，但我并没有试图创建一个新用户，只是通过一个关系表将两者链接起来。

  public class ApplicationUser : IdentityUser
{
    public async Task<ClaimsIdentity> GenerateUserIdentityAsync(UserManager<ApplicationUser> manager)
    {
        // Note the authenticationType must match the one defined in CookieAuthenticationOptions.AuthenticationType
        var userIdentity = await manager.CreateIdentityAsync(this, DefaultAuthenticationTypes.ApplicationCookie);
        // Add custom user claims here
        userIdentity.AddClaim(new Claim("FirstName", this.FirstName.ToString()));
        userIdentity.AddClaim(new Claim("LastName", this.LastName.ToString()));
        return userIdentity;
    }
    public ApplicationUser()
    {
        this.Companies = new List<Company>();
    }

    public string FirstName { get; set; }
    public string LastName { get; set; }
    public virtual List<Company> Companies { get; set; }
}

 [HttpPost]
    public async Task<ActionResult> CreateCompany(CreateCompanyViewModel model)
    {

        if (ModelState.IsValid)
        {


            DAL.CompanyContext context = new DAL.CompanyContext();

            // Creating object from recieved form
            DomainModels.Company newCompany = new DomainModels.Company();


            newCompany.Address = model.Address;
            newCompany.BillingEmail = model.BillingEmail;
            newCompany.City = model.City;
            newCompany.Cvr = model.Cvr;
            newCompany.Email = model.Email;
            newCompany.Name = model.Name;
            newCompany.Telephone = model.Telephone;
            newCompany.Website = model.Website;
            newCompany.Zip = model.Zip;
            newCompany.UserId = model.SelectedApplicationUserId;
            // adding and saving
            context.Companies.Add(newCompany);
            await context.SaveChangesAsync();

            return RedirectToAction("Index");
        }
        return View(model);

    }

 public DbSet<Company> Companies { get; set; }
    protected override void OnModelCreating(DbModelBuilder mb) 
    {
        base.OnModelCreating(mb);
        mb.Entity<Company>() 
            .HasMany(c => c.Users)
            .WithMany(d =>d.Companies)
            .Map(m=>
            {
            m.MapLeftKey("Company_ID");
            m.MapRightKey("ApplicationUser_Id");
            m.ToTable("CompanyApplicationUsers");
            });
    }

    }

       [HttpPost]
    public async Task<ActionResult> CreateCompany(CreateCompanyViewModel model)
    {

        if (ModelState.IsValid)
        {


            DAL.CompanyContext context = new DAL.CompanyContext();

            // Creating object from recieved form
            DomainModels.Company newCompany = new DomainModels.Company();


            newCompany.Address = model.Address;
            newCompany.BillingEmail = model.BillingEmail;
            newCompany.City = model.City;
            newCompany.Cvr = model.Cvr;
            newCompany.Email = model.Email;
            newCompany.Name = model.Name;
            newCompany.Telephone = model.Telephone;
            newCompany.Website = model.Website;
            newCompany.Zip = model.Zip;
            foreach (string i in model.SelectedApplicationUserId)
            {
                ApplicationUser user = new ApplicationUser();
                user.Id = i;
                newCompany.Users.Add(user);
            }
            //newCompany.Users = model.SelectedApplicationUserId;
            // adding and saving
            context.Companies.Add(newCompany);
            await context.SaveChangesAsync();

            return RedirectToAction("Index");
        }
        return View(model);

    }

    //newCompany.Users = model.SelectedApplicationUserId;
            // adding and saving

            context.Companies.Add(newCompany);
            try
            {
               int response = await context.SaveChangesAsync();
            }
            catch(Exception exception)
            {

            }

            foreach (string i in model.SelectedApplicationUserId)
            {
                var user = await UserManager.FindByIdAsync(i);
                user.CompanyId = newCompany.ID;
                IdentityResult result = await UserManager.UpdateAsync(user);
            }
            try
            {

            }
            catch (Exception exception)
            {
                throw;
            }

            return RedirectToAction("Index");
        }
        return View(model);

var userList = new List<ApplicationUser>();
foreach (string i in model.SelectedApplicationUserIds)
{
    userList.Add(new ApplicationUser {Id = i});
}

var newCompany = new Company
{
    Address = model.Address;
    BillingEmail = model.BillingEmail;
    City = model.City;
    // etc. 
    Users = userList
};

int response = await context.SaveChangesAsync();