inheritance - How to create inherited object using GlobalContainer (Spring4D framework) in Delphi? -

i have problem in creating custom class object inherited using globalcontainer of spring4d framework.

parent class:

type   tvspsection = class ( tinterfacedobject, ivspsection )    private         _id : integer;         _organization : idirectoryobject;          function getid () : integer;         procedure setid ( const value : integer );         function getorganization () : idirectoryobject;         procedure setorganization ( const value : idirectoryobject );    public         property id : integer read getid write setid;         property organization : idirectoryobject read getorganization write setorganization;  end;  ...  initialization    globalcontainer.registertype<tvspsection>.implements<ivspsection>.         injectfield ( '_organization' )         ; 

descendant class:

type   tvspseismicsection = class ( tvspsection, ivspseismicsection, iinterface )    private         _report : ireport;          function getreport () : ireport;         procedure setreport ( const value : ireport );    public         property report : ireport read getreport write setreport;  end;  ...  initialization    globalcontainer.registertype<tvspseismicsection>.implements<ivspseismicsection>.         injectfield ( '_report' )         ;  end. 

and attempt create object of tvspseismicsection:

_seismicsection : ivspseismicsection; _seismicsection := globalcontainer.resolve<ivspseismicsection>; 

next, try access 'organization' field (of parent class) , access violation error.

 _seismicsection.organization.id := -1;    <- exception here 

so, question how tell parent class initiate fields using globalcontainer resolver? maybe via delegateto method, how?

one way have found initiate parent fields in descendant class's constructor this:

constructor tvspseismicsection.create (); begin    organization := globalcontainer.resolve<idirectoryobject>;  end; 

but violates dependency injection paradigm, because have include additional classes (idirectoryobject) descendant class.

there several ways , depends best. dependencies required should passed constructor arguments , optional should passed property injection.

so if add constructor taking idirectoryobject argument tvspsection class container able satisfy argument if knows how resolve idirectoryobject.

that cleanest way 1 rule using di container write code still di container agnostic , use container tool not dependency.

if want keep property injection using inject attribute on property should work (don't forget add spring.container.common uses attribute) specifying injectproperty in registration (while possible avoid field injection doable rtti , not regular code - see previous paragraph).