Foreign Key Object returning null when I call from ApplicationDbContext

Question

I got a problem on Foreign Keys.

What I want is that for every Video Model there is a Profile Model link to it

An example of that would look like this:

public class VideoModels
{ 
    [Required]
    public int Id { get; set; } 
    public ProfileModels Profile { get; set; }  
}

While in the ProfileModels

public class ProfileModels
{ 
    [Required]
    public int Id { get; set; }
    public string Title { get; set; }  
}

Which technically should not have any connection with VideoModels for the VideoModels is dependent with ProfileModels and there can be 0 to many relationship.

So after that I tested it, my VideoModels has a Profile_Id parameter which is a foreign key from ProfileModels

But after creating an object and retrieving it, it returns NULL but when I check the database there is an existing Foreign Key Id.

Please help, stuck here for hours now

Answer 1

Profile would be null here due to LazyLoading. This allows us to have an object with many different objects that are only loaded when needed rather than loaded when a parent object is loaded. This is especially helpful if you have something like a Comments property as part of the user. Without LazyLoading the comments collection would be loaded whenever you wanted to grab just the VideoModels.ID. A downside to LazyLoading is that each navigation performed requires a separate query to the data source.

To allow for LazyLoading you need to mark related object properties as virtual.

In addition you must supply a navigation property in your context:

public class Database : DbContext {
    public DbSet<VideoModels> People { get; set; }
    public DbSet<ProfileModels> PersonDetails { get; set; }
}

Or

If you want to use your current class modeling, you can achieve this by disabling LazyLoading.

this.Configuration.LazyLoadingEnabled = false;

Answer 2

Nevermind, I just forgot to make the foreign key propery as virtual.

public class VideoModels
{ 
    [Required]
    public int Id { get; set; } 
    public virtual ProfileModels Profile { get; set; }  
}