asp.net - How to change the ID of a complex type property in entity framework without first selecting the object? -

if have object property of complex type object b, how can change a.b b object without first selecting new b object?

for example, know can this

a.b = (from b in db.bs b.id = newid select b).first() 

but rather this

a.b.id = newid 

and assume can't because overwrite properties of existing b object empty values

b = new b { .id = newid } db.bs.attach(b) a.b = b 

you have a.b property call constructor on demand when b not yet initialized.

i converted c# vb.net without testing it, same pattern works everywhere. make sure initialize property nothing or null first, , in property accessor call constructor if private member variable not initialized. return value usual.

public class b     public property id() [string]                     return m_id         end         set             m_id = value         end set     end property     private m_id [string] end class public class     private _b b     public sub new()         _b = nothing     end sub     public property b() b                     if _b nothing                 _b = new b()             end if             return _b         end         set             _b = value         end set     end property end class 

and can set properties on a.b impunity!

dim new a() a.b.id = "b created on demand!"