c# - EntityState clarification with SaveChanges -

i used technique shows in answer ( https://stackoverflow.com/a/6282472/2045385 ) create trackingdbcontext inherit many of contexts now, , entity needs createdate/lastmodified properties inherits trackingbase entity. has worked far.

until today.

ultimately fixed problem changing way add new entity collection, don't understand why original isn't working... , i'd understand figure going come bite me again , again until understand it.

originally adding new status record orderitem creating new status object , adding collection of statusitems of order object, so.

        var newlypaidorders = shopdb.shoporders             .where(o => o.status == "new" &&                           o.payment >= o.cost)             .tolist();          (int = 0; i< newlypaidorders.count; i++)          {             var paidorder = newlypaidorders.elementat(i);             foreach ( var paiditem in paidorder.orderitems )             {                 shoporderitemstatus sois = new shoporderitemstatus                 {                     status = "paid",                     agent = "cronjob",                     shoporderitem = paiditem,                     comment = ""                 };                 paiditem.shopitemorderstatus.add(sois);             }             paidorder.status = "paid";         }         if (newlypaidorders.count > 0)             shopdb.savechanges(); 

after savechanges() can see new status object created in database, but.... hey! createdate/lastmodified not updated, both null. put in breakpoints trackingdbcontext.savechanges() , sure enough, filter searching entities modified or added coming empty. whoah.. how can be?

ienumerable<objectstateentry> objectstateentries =     e in context.objectstatemanager.getobjectstateentries(entitystate.added | entitystate.modified)                     e.isrelationship == false &&             e.entity != null &&             typeof(timestamptrackingbase).isassignablefrom(e.entity.gettype())         select e; 

this morning got and, case, sleep gives new perspective. decided add item context.dbset directly rather modifying object had in hands, see if there difference, so.

        (int = 0; i< newlypaidorders.count; i++)          {             var paidorder = newlypaidorders.elementat(i);             foreach ( var paiditem in paidorder.orderitems )             {                 shoporderitemstatus sois = new shoporderitemstatus                 {                     status = "paid",                     agent = "cronjob",                     shoporderitem = paiditem,                     comment = ""                 };                 shopdb.shoporderitemstatus.add(sois);             }             paidorder.status = "paid";         } 

and there is.. works intended, createdate/modifieddates not null. why original not work? can't head around concept (a) new entity added database.. automatic detectchanges() system must working... , surely had "added()" state... (b) somehow state not sufficient found in filter newly added items , created/modifieddate fields weren't updated.