在ASP.NET MVC 4中设置外键

Question

I have 2 models and want to create a foreign key relationship. Basically each note should be assigned to a user.

[Table("UserProfile")]
public class UserProfile
{
    [Key]
    [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
    public int UserId { get; set; }
    public string UserName { get; set; }
    public string Email { get; set; }
}

[Table("UserNotes")]
public class UserNotes
{
    [Key]
    [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
    public int NoteId { get; set; }

    [ForeignKey("UserProfile")]
    public virtual int UserId { get; set; }

    public string Title { get; set; }
    public string Content { get; set; }
    public string Added { get; set; }
    public DateTime? Edited { get; set; }  
}

When I attempt to add new user note I get: The ForeignKeyAttribute on property 'UserId' on type 'note.DO.Models.UserNotes' is not valid. The navigation property 'UserProfile' was not found on the dependent type 'note.DO.Models.UserNotes'. The Name value should be a valid navigation property name.

I have tried a lot of combinations including those found in similar questions but none of them worked.

Answer 1

Try this :

public virtual int UserId { get; set; }

[ForeignKey("UserId")]
public virtual UserProfile User { get; set; }

This way, you pair foreign key property with navigation property.

Edit : you can also write it like this :

[ForeignKey("UserProfile")]
public virtual int UserId { get; set; }

public virtual UserProfile UserProfile { get; set; }

Those two snippets gives the same result. Your error message says that "UserProfile" property is missing, you just have to add it.