与身份服务器的m2m EF关系

Question

我使用身份服务器aspNetUsers表，其中放置了所有已注册的用户。我用userId和我的自定义表之间的外主键关系来构建自定义表，从这里我要建立m2m关系。用户的编程语言及其知识。但是，即使使用JOIN TABLE也不能使用。在受保护的覆盖void OnModelCreating(ModelBuilder modelBuilder)方法上，它给了我这个错误：

The ALTER TABLE statement conflicted with the FOREIGN KEY constraint "FK_userPLs_Knowledge_KnowledgeId". The conflict occurred in database "try1", table "dbo.Knowledge", column 'KnowledgeId'

我的代码如下：

    public class ApplicationUser : IdentityUser
    {
        //s
        public string ImgPath { get; set; }

        public UserPL UserPL { get; set; }
    }


//USERiD HERE IS THE FOREIGN KEY CONNECTED WITH THE PRIMARY KEH OF THE ID
//OF THE ApplicationUser AND IT IS WORKING
 public class UserPL
    {
        public string UserPLId { get; set; }

        public string UserId { get; set; }


        public string Name { get; set; }

        public string ProgrammingLanguageId { get; set; }


        public string KnowledgeId { get; set; }

        public ProgrammingLanguage ProgrammingLanguage { get; set; }

        public Knowledge Knowledge { get; set; }

        public ApplicationUser applicationUser { get; set; }

    }


public class ProgrammingLanguage
    {
        public string ProgrammingLanguageId { get; set; }
        public string Name { get; set; }

        public  ICollection<UserPL> UserPLs { get; set; }

    }


  public class Knowledge
    {
        public string KnowledgeId { get; set; }
        public string Name { get; set; }


        public ICollection<UserPL> UserPLs { get; set; }

    }


//THE CONEXT


public class AuthenticationContext : IdentityDbContext
    {
        public AuthenticationContext(DbContextOptions options) : base(options)
        {

        }

        public DbSet<ApplicationUser> ApplicationUsers { get; set; }


        public DbSet<UserPL> userPLs { get; set; }

        public DbSet<ProgrammingLanguage> ProgrammingLanguages { get; set; }
        public DbSet<Knowledge> Knowledges { get; set; }


        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
//this is not working,it gives the above error
            base.OnModelCreating(modelBuilder);
            //modelBuilder.Entity<UserPL>().HasKey(sc => new { sc.ProgrammingLanguageId, sc.KnowledgeId });


            modelBuilder.Entity<UserPL>()
                .HasKey(bc => new { bc.KnowledgeId, bc.ProgrammingLanguageId });
            modelBuilder.Entity<UserPL>()
                .HasOne(bc => bc.Knowledge)
                .WithMany(b => b.UserPLs)
                .HasForeignKey(bc => bc.KnowledgeId);
            modelBuilder.Entity<UserPL>()
                .HasOne(bc => bc.ProgrammingLanguage)
                .WithMany(c => c.UserPLs)
                .HasForeignKey(bc => bc.ProgrammingLanguageId);

//THIS WORKS
            modelBuilder.Entity<ApplicationUser>()
            .HasOne<UserPL>(s => s.UserPL)
            .WithOne(ad => ad.applicationUser)
            .HasForeignKey<UserPL>(ad => ad.UserId);




        }