private AdditionalInfo ValidateProperties(AdditionalInfo additionalInfo) { if (additionalInfo.Event == null) { return(AdditionalInfo.Empty()); } // Assign properties additionalInfo.Event = Context.CheckCenterEvents.Find(additionalInfo.Event.Id); // Do not overwrite existing entities Context.Entry(additionalInfo.Event).State = EntityState.Unchanged; return(additionalInfo); }