entity framework - How to Update a List of entities properly? -

i update list of entities, using ef4.

1. i have viewmodel object (retrieved web form) passed method named "producttoupdate" contains list "labels".

2. i corresponding list of objects database linq query anonymous object named "requetevalslabels" did manually (testing id's in foreach loop) follow, imagine not best way it?

   for (int = 0; < producttoupdate.labels.count; i++)         {             foreach (var item in producttoupdate.labels)             {                 if (requetevalslabels[i].id == item.idvaleurlabel){                 requetevalslabels[i].valeur = item.valeur;                 }             }         } 

you may want use following pattern

        foreach (var item in producttoupdate.labels) {             entity e = new entity { id = item.idvaleurlabel};             context.entityset.attach(e);             e.valeur = item.valeur;         } 

this prevent loading (select) trip database but:

• as no load occur, can't sure id exists in db, may have an insert exception trying update non existing row.
• as no load occur, can't check label modification , may update same value.