将 API 到 POST 写入多对多关系

Question

大家晚上好

对于有经验的开发人员来说，这可能是一个简单的问题，但我是 C# 的新手，ASP.Net 和 Entity Framework。我有两个 tables - AppUser 和 CompanySettings。这2个table之间是多对多的关系。


    public class AppUser
    {
        public int Id { get; set; }
        public string UserName { get; set; }
        public byte[] PasswordHash { get; set; }
        public byte[] PasswordSalt { get; set; }
        public string KnownAs { get; set; }
        public DateTime Created { get; set; } = DateTime.Now;
        public DateTime LastActive {get; set;} = DateTime.Now;
        public ICollection<Photo> Photos { get; set; }

        public virtual ICollection<AppUserCompanySettings> AppUserCompanySettings { get; set; }
    }


public class CompanySettings
    {
        public int Id { get; set; }
        public string CompanyName { get; set; }
        public string CompanyRegistrationNumber { get; set; }
        public bool isActive { get; set; }
        public bool isArchived { get; set; }
        public virtual ICollection<AppUserCompanySettings> AppUserCompanySettings { get; set; }

    }

我还创建了连接 table:

public class AppUserCompanySettings
    {
        public int Id { get; set; }
        public int AppUserId { get; set; }
        public virtual AppUser AppUser { get; set; }
        public int CompanySettingsId { get; set; }
        public virtual CompanySettings CompanySettings { get; set; }
    }

我的 API 现在看起来像这样：

public async Task<ActionResult<CompanySettings>> AddNewCompany(CompanySettings companySettings)
        {
            if (await CompanyExists(companySettings.CompanyRegistrationNumber)) return
                BadRequest("Company already exists.  Please contact our Support team for assistance");

            var user = new AppUser {
                Id = 1
            };

            var company = new CompanySettings
            {
                CompanyName = companySettings.CompanyName,
                CompanyRegistrationNumber = companySettings.CompanyRegistrationNumber,
                isActive = companySettings.isActive,
                isArchived = companySettings.isArchived,
            };

            _context.CompanySettings.Add(company);
            _context.Update(user);
            await _context.SaveChangesAsync();

            return company;
        }

用户注册 - 这会将用户名和密码写入 AppUser table。他不需要在注册时创建公司。

但是，当他想添加公司（写入公司设置）时，我如何将 API 到 post 写入 CompanySettings table 以及EF 创建的 AppuserCompanySettings table?

目前，如果我调用 API，它会创建公司。但它不会加入 AppUserCompanySettings。

如何更新加入 table？

Answer 1

确保你在你的 DbContext 配置中加入这个：

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    base.OnModelCreating(modelBuilder);

    modelBuilder.Entity<AppUser>()
        .HasMany(x => x.AppUserCompanySettings )
        .WithOne(x => x.AppUser)
        .HasForeignKey(x => x.AppUserId);

    modelBuilder.Entity<CompanySettings>()
        .HasMany(x => x.AppUserCompanySettings)
        .WithOne(x => x.CompanySettings)
        .HasForeignKey(x => x.CompanySettingsId);

    modelBuilder.Entity<AppUserCompanySettings>()
        .HasKey(x => new {x.AppUserId, x.CompanySettingsId});

}

从您的 AppUserCompanySettings 中替换 public int Id { get; set; }，因为您的 table 中只有 2 个外键，它们的作用类似于主键

这段代码之后：

var user = new AppUser 
{
    Id = 1
};

var company = new CompanySettings
{
    CompanyName = companySettings.CompanyName,
    CompanyRegistrationNumber = companySettings.CompanyRegistrationNumber,
    isActive = companySettings.isActive,
    isArchived = companySettings.isArchived,
};

你必须这样做：

// adding relationship between entities here
user.AppUserCompanySettings.Add(new AppUserCompanySettings 
{
    AppUser = user, 
    CompanySettings = company
});

// if you haven't created a new user but used already existing - 
// replace Add with Update
_context.Add(user);
_context.SaveChanges();

也像这样修改 AppUser 和 CompanySettings 中的 Collections

public virtual ICollection<AppUserCompanySettings> AppUserCompanySettings { get; set; } = new List<AppUserCompanySettings>();

将 API 到 POST 写入多对多关系

Writing an API to POST to a many-to-many relationship

c#

asp.net

api

many-to-many

entity-framework