无法映射属性“属性名称”，因为它属于“对象”类型，不是受支持的原始类型或有效的实体类型

Question

I am trying to make a table that has 2 one to many relatishops attached to it.

After some tries I fixed what I could and I am stuck at that error.

The property 'Property Name' could not be mapped, because it is of type 'object' which is not a supported primitive type or a valid entity type.

DbContext class for fluentAPI

public class ApplicationDbContext : IdentityDbContext
   {
       public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
           : base(options)
       {
       }

       public DbSet<Account> Accounts { get; set; }

       public DbSet<Transaction> Transactions { get; set; }

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

           modelBuilder.Entity<Transaction>()
               .HasOne(p => p.Receiver)
               .WithMany(t => t.ReceiveTransactions)
               .HasForeignKey(m => m.ReceiverID)
               .OnDelete(DeleteBehavior.Restrict);

           modelBuilder.Entity<Transaction>()
               .HasOne(p => p.Sender)
               .WithMany(t => t.SendTransactions)
               .HasForeignKey(m => m.SenderID)
               .OnDelete(DeleteBehavior.Restrict);
       }

   }

And here are the rest of the classes

User Class

public class ApplicationUser : IdentityUser
    {
        public ICollection<Transaction> SendTransactions { get; set; }
        public ICollection<Transaction> ReceiveTransactions { get; set; }
        public Account Account { get; set; }


        public ApplicationUser()
        {
        }
    }

Transaction

public class Transaction
    {
        [Key]
        public String TransactionID { get; set; }

        public String SenderID { get; set; }

        public String ReceiverID { get; set; }

        [DataType(DataType.DateTime)]
        public DateTime Date { get; set; }

        public String Currency { get; set; }

        public float Amount { get; set; }

        [ForeignKey("SenderID")]
        public ApplicationUser Sender { get; set; }

        [ForeignKey("ReceiverID")]
        public ApplicationUser Receiver { get; set; }
        public object ReceiverId { get; internal set; }

        public Transaction(String TransactionID, String SenderID, String ReceiverID, DateTime Date, String Currency, float Amount)
        {
            this.TransactionID = TransactionID;
            this.SenderID = SenderID;
            this.ReceiverID = ReceiverID;
            this.Date = Date;
            this.Currency = Currency;
            this.Amount = Amount;
        }
    }

Answer 1

public object ReceiverId { get; internal set; }

This property is causing the error, because it is not a type that entity framework recognizes for mapping. Either change the data type to a primitive like int or string, or remove the property.