EF Code First使用现有映射类进行多对多映射

Question

I have three classes

public class User
{
    public int Id { get; set; }
    public string Name { get; set; }
    public virtual ICollection<Product> Products { get; set; }
}

public class Product
{
    public int Id { get; set; }
    public string Name { get; set; }
    public virtual ICollection<User> Users { get; set; }
}

public class ProductXUser // Mapping class
{
    public int Id { get; set; }
    public int User_Id { get; set; }
    public int Product_Id { get; set; }
    public DateTime DateMapped { get; set; }
}

How can i map a many to many relationship (using Fluent API) between User class and Product class using ProductXUser class as the mapping table?

Answer 1

You can't. Once you expose junction table as entity you cannot use many-to-many relation. You must instead use two one-to-many relations. One from User to ProductXUser and second from Product to ProductXUser . You must also change navigation properties in both Product and User to point to collection of ProductXUser . Direct many-to-many relation works only when you do not expose junction table as an entity.