使用对象集合进行 EF Core 播种

如何解决使用对象集合进行 EF Core 播种

我需要用种子数据填充数据库（sql 服务器）。

对于“实习”表，我尝试输入名为 DesiredSkills 的集合，但是当我运行迁移时，我收到以下错误消息：“未将对象引用设置为对象的实例。”

是否可以使用列表之类的集合为数据库做种？

数据库上下文：

public InternshipdbContext(DbContextOptions<InternshipdbContext> options) : base(options)
        {

        }
        public DbSet<Avatar> Avatars { get; set; }
        public DbSet<Company> Companies { get; set; }
        public DbSet<Internship> Internships { get; set; }
        public DbSet<Login> Logins { get; set; }
        public DbSet<Skill> Skills { get; set; }
        public DbSet<Trainee> Trainees { get; set; }
        public DbSet<TraineeRequest> TraineeRequests { get; set; }
        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.SharedTypeEntity<Dictionary<string,object>>("InternshipSkill");

            modelBuilder.Entity<Trainee>()
                .HasOne(x => x.Login)
                .WithMany()
                .OnDelete(DeleteBehavior.NoAction);

            modelBuilder.Entity<Internship>()
                .HasOne(x => x.Company)
                .WithMany()
                .OnDelete(DeleteBehavior.NoAction);

            modelBuilder.ApplyConfiguration(new LoginConfiguration());
            modelBuilder.ApplyConfiguration(new AvatarConfiguration());
            modelBuilder.ApplyConfiguration(new CompanyConfiguration());
            modelBuilder.ApplyConfiguration(new TraineeConfiguration());
            modelBuilder.ApplyConfiguration(new SkillConfiguration());
            modelBuilder.ApplyConfiguration(new InternshipConfiguration());
            modelBuilder.ApplyConfiguration(new TraineeRequestConfiguration());
        }

实习配置：

 public void Configure(EntityTypeBuilder<Internship> builder)
        {
            builder.HasData(
                new Internship { Id = 1,CompanyId = 1,CreationDate = DateTime.Now,Title = "Stage Software Developer",StartDate = DateTime.Now.AddDays(30),EndDate = DateTime.Now.AddDays(60),DesiredSkills = { new Skill { Id = 1,Name = "C#" },new Skill { Id = 2,Name = "sql" } },FullTimeOrPartTime = InternshipType.Fulltime,IsRemote = RemoteExpectation.Whatever,PaymentExpectation = PaymentExpectation.Whatever,DescriptionFileUpload = uploadlink1,ShortDescription = "Wij zijn op zoek naar een schitterende Software Developer" },new Internship { Id = 2,CompanyId = 2,Title = "Stage Android Developer",StartDate = DateTime.Now.AddDays(32),EndDate = DateTime.Now.AddDays(62),new Skill { Id = 10,Name = "Xamarin" } },DescriptionFileUpload = uploadlink2,ShortDescription = "Wij zijn op zoek naar een schitterende Android Developer" },new Internship { Id = 3,CompanyId = 3,Title = "Stage Angular Developer",StartDate = DateTime.Now.AddDays(35),EndDate = DateTime.Now.AddDays(65),new Skill { Id = 4,Name = "Angular" } },DescriptionFileUpload = uploadlink3,ShortDescription = "Wij zijn op zoek naar een schitterende Angular Developer" },new Internship { Id = 4,Title = "Stage Java Developer",DesiredSkills = { new Skill { Id = 7,Name = "Java" },DescriptionFileUpload = uploadlink4,ShortDescription = "Wij zijn op zoek naar een schitterende Java Developer" },new Internship { Id = 5,CompanyId = 4,new Skill { Id = 1,Name = "C#" } },DescriptionFileUpload = uploadlink5,ShortDescription = "Wij zijn op zoek naar een geniaal Sotftware Developer" },new Internship { Id = 6,CompanyId = 5,Title = "Stage Sotware Developer",DesiredSkills = { new Skill { Id = 12,Name = "C++" },DescriptionFileUpload = uploadlink6,ShortDescription = "Wij zijn op zoek naar een bliljant Software Developer" }
                );
        }