EntityFramework代码第一个异常

Question

i when i try to save my entitie buzzmate i have this exception :

     An entity object cannot be referenced by multiple instances of IEntityChangeTracker.

this is the code that generate this exception :

        var p = Session["mayaProfile"] as MayaProfile;
        BuzzMate buzzmate = new BuzzMate();
        buzzmate.MayaProfile = p;
        SocialBuzzCompaign socialcampaign = _buzzService.GetSocialBuzzCompaign(model.socialBuzzCompaignId);
        //Ajouter le BuzzMate
        buzzmate.SocialBuzzCompaign = socialcampaign;
        buzzmate.JoiningStatus = JoiningStatus.Approved;
        buzzmate.SelectionType = BuzzMateSelectionType.InvitedByBuzzLeader;                     
        //try
        //
        _buzzService.AddBuzzMate(buzzmate);

and this is method AddBuzzMate :

    public void AddBuzzMate(BuzzMate buzzMate)
    {
        _buzzMateRepository.Insert(buzzMate);
        _buzzMateRepository.Save();
    }

when i try to save buzzmate i have exception

Answer 1

The problem is most probably p . Don't use entities stored in session for persistence or you will not avoid this error. Try to create clone of p and assign it to buzzmate and if you use same EF context for loading socialcampaign and persisting buzzmate it should work.