实体框架不会加载导航属性

Question

I am using EF with POCO for one of my projects.

The data context and pocos have been created successfully and I can fetch the data. There is one problem: the navigation properties are always null.

I've got these two classes :

public class UserProfile {

public string Username { get; set; }
public int RoleId { get; set; }
public virtual SecurityRole SecurityRole { get; set; }

}

public class SecurityRole {

public int roleId { get; set; }
public string RoleDescription { get; set; }

}

public class DataContext : ObjectContext {

public ObjectSet<UserProfile> UserProfiles { get; set; }
public ObjectSet<SecurityRole> SecurityRoles { get; set; }

public DataContext() : base("name=datacontext_entities", "datacontext_entities") {

UserProfiles = CreateObjectSet<UserProfile>();
SecurityRole = CreateObjectSet<SecurityRole>();

}

}

The database contains objects from userprofile and securityrole. The foreign keys are set. I do access those elements by the simple linq query : Db.UserProfile.FirstOrDefault(f => f.Username == username); where Db is my datacontext.

The whole user profile object will have data but the navigation property SecurityRole is always null.

Am I missing something ?

Answer 1

I think the way EF code first works you should have the Id property on youur SecurityRole class as SecurityRoleId or something or apply a [Key] attribute to it. It should work then

public class SecurityRole 
{
    [Key]
    public int roleId { get; set; }
    public string RoleDescription { get; set; }

}

or

public class SecurityRole 
{
    public int SecurityRoleId { get; set; }
    public string RoleDescription { get; set; }

}