外键MVC 4代码优先C＃

Question

How can i add a foreign key to a Model (code first)

i have a model Product which has an ID (primary key) which i want to add to my model order like.

public class Order
{
 public int ID {get; set;}

 [Required]
 public int Total {get; set;}    

 [Required]
 public int ProductId{get; set;}
}

but how can i make the ProductId refer to the id of my Product model like a foreign key? On Stackoverflow there are alot simmilar questions but all with different answers, but they arent working for me. I really hope someone has a solution or can points me in the right direction with an explanation.

Answer 1

You need to add a navigation property:

public virtual Product Product { get; set; }

So the Order class will look like this:

public class Order
{
    public int ID {get; set;}

    [Required]
    public int Total {get; set;}    

    [Required]
    public int ProductId{get; set;}

    [Required]
    public virtual Product Product { get; set; }
}

Also, strictly speaking the ProductId property isn't needed once you have the virtual Product property.

Answer 2

You could do something like this:

public class Order
{
 public int ID {get; set;}

 [Required]
 public int Total {get; set;}    

 [Required]
 public int ProductId{get; set;}

 [ForeignKey("ProductId")]
 public virtual Product Product {get; set;}

}