c# - Loading grandchild object in child collection, EF -

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• include grandchildren in ef query 2 answers

model:

    public class parent     {         public int id { get; set; }         public icollection<child> children { get; set; }     }      public class child     {         public int id { get; set; }         public int idgrandchild { get; set; }         public virtual grandchild grandchild { get; set; }     }      public class grandchild     {         public int id { get; set; }     } 

i have existing parent entity children collection. after operations want load newly added children objects parent's collection database this

_context.entry(parent).collection(f => f.children).load(); 

but when doing that, grandchild object in every newly added collection element null. tried include grandchild in way still grandchild object null.

_context.entry(parent).collection(f => f.children).query().include(c => c.grandchild).load(); 

how correctly load new items parent's children collection including grandchild objects?

edit: dont know why question marked duplicate? problem is: have existing (loaded/tracked) parent entity in 1 context instance (form) , in context instance (form) modified entity child's collection ( add or remove child). want load these newly added entries parent entity collection in first context instance using 1 of written methods after newly added object loaded grandchild's nulls. don't know how correctly load these new child objects existed (tracked) parent entity without getting nulls.

i use following(wihout load)

parent parent = _context.parent.include(p => p.children.grandchild).firstordefault(); 

and if grandchild collection, use

parent parent = _context.parent.include(p => p.children.select(c => c.grandchild).firstordefault();