c# - Filling Foreign Key Object in Entity Framework 4 -

i using entityframework first time , maybe question simple...i've used code first method..i have class personnel looks this:

public class personnel {      public string id { set; get; }     public int code { set; get; }     public string name { set; get; }     public int type { set; get; }      public jobtitle title { set; get; } } 

and jobtitle class:

public class jobtitle {     public string id { set; get; }     public int number { set; get; }     public string title { set; get; }      public list<personnel> personnels { set; get; }  } 

which last property in personnel class foreign key in personnel table of course..my problem when want retrieve personnels ( or personnel ) db using lambda expression..the foreign key object null..the lambda expression below:

context.contextinstance.personnels.tolist(); 

and if change expression foreign key object not null more.

 context.contextinstance.personnels.include("title").tolist(); 

is right way??..is there better way??..i supposed ef automatically understand that!!!!..if there more 1 fk have use include of them?? please me understand.

thanks

this due lazy loading. when call context.contextinstance.personnels.tolist(); fetch personnel's title not fetch until instanced, make virtual it.

or, can disable lazy loading

public myentitiescontext() : base("name=myentitiescontext", "myentitiescontext") {      this.configuration.lazyloadingenabled = false; } 

doing related data context. using "include" loading on demand, when specify properties want query.

virtual keyword allows entity framework runtime create dynamic proxies entity classes , properties, , support lazy loading. without virtual, lazy loading not supported, , null on collection properties.