Unable to determine the relationship represented by navigation 'Customer.BoughtProducts' of type 'ICollection'

Question

I have 3 models and a User class which defines the common properties for customer and seller so I won't attach it (I guess it would be useless info).

public class Seller : User
{
    public bool IsApproved { get; set; }

    public ICollection<Product> WaitingForShipping { get; set; }

    public ICollection<Product> ProductsOnSell { get; set; }
} 

public class Customer : User
{
    public bool IsSubscriber { get; set; }

    public ICollection<Product> WaitingForReceiving { get; set; }

    public ICollection<Product> BoughtProducts { get; set; }
}

public class Product
{
    [Key] public Guid Id { get; set; }

    public string Name { get; set; }

    public decimal Price { get; set; }

    public string Description { get; set; }

    public ProductCategory Category { get; set; }

    public int SellerId { get; set; }
    [ForeignKey("SellerId")] public Seller ProductSeller { get; set; }

    public int CustomerId { get; set; }

    [ForeignKey("CustomerId")] public Customer ProductCustomer { get; set; }

    public ICollection<Characteristic> ProductInfo { get; set; }

    public ICollection<Image> ImagesURLs { get; set; }

    public long Quantity { get; set; }

    public long AmountSold { get; set; }

    public byte Rating { get; set; }

    public bool InStock { get; set; }
}

And the last is the DbContext class

public class AppDbContext : DbContext
{
    public DbSet<Customer> Customers { get; set; }

    public DbSet<Seller> Sellers { get; set; }

    public DbSet<Product> Products { get; set; }

    public AppDbContext(DbContextOptions<AppDbContext> options) : base(options) { }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        
        // There were a lot of useless tries of configuring the relationships like
        // this
        // modelBuilder.Entity<Customer>().HasMany(prods => prods.BoughtProducts)
        // .WithOne(s => s.ProductSeller).HasForeignKey(i => i.SellerId);
        base.OnModelCreating(modelBuilder);
    }
}

When I use:

dotnet ef migrations add inital

into the terminal I get this:

Unable to determine the relationship represented by navigation'Customer.BoughtProducts' of type 'ICollection'. Either manually configure the relationship, or ignore this property using the '[NotMapped]' attribute or by using 'EntityTypeBuilder.Ignore' in 'OnModelCreating'.

I have no idea how to fix it.

Answer 1

I don't know your Customer's code. But I guess you maybe use ICollection<Product> for more than one. Take seller as an example.

According to your Seller.cs, I add below code in Product,

        public Guid SellerId { get; set; }
        public Seller ProductSeller { get; set; }

        public Guid OnSellId { get; set; }
        public Seller OnSell { get; set; }

And add .OnDelete(DeleteBehavior.Restrict); in Context

 protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<Product>()
       .HasOne(p => p.ProductSeller)
       .WithMany(t => t.WaitingForShipping)
       .HasForeignKey(m => m.SellerId)
       .OnDelete(DeleteBehavior.Restrict);

            modelBuilder.Entity<Product>()
                .HasOne(p => p.OnSell)
                .WithMany(t => t.ProductsOnSell)
                .HasForeignKey(m => m.OnSellId)
                .OnDelete(DeleteBehavior.Restrict);


        }

It works, My customer.cs is below.If your Customer.cs like seller, change code in Product and Context like me.

public class Customer
    {
        public int CustomerId { get; set; }
        public string CustomerName { get; set; }
      
       
        public ICollection<Product> BoughtProducts { get; set; }
       
    }

Update for Customer

Add in Context:

modelBuilder.Entity<Product>()
       .HasOne(p => p.ProductCustomer)
       .WithMany(t => t.WaitingForReceiving)
       .HasForeignKey(m => m.CustomerId)
       .OnDelete(DeleteBehavior.Restrict);

            modelBuilder.Entity<Product>()
                .HasOne(p => p.BoughtCustomer)
                .WithMany(t => t.BoughtProducts)
                .HasForeignKey(m => m.BoughtId)
                .OnDelete(DeleteBehavior.Restrict);

Add in product:

       public Guid CustomerId { get; set; }
       public Customer ProductCustomer { get; set; }
        
        public Guid BoughtId { get; set; }
        public Customer BoughtCustomer { get; set; }