public static async Task AddAccountItems(List <Item> items, string apiKey) { using (var db = new UserContextFactory().CreateDbContext()) { var user = await GetUser(apiKey); if (user == null) { return; } var currentItems = await db.Item.Where(x => x.UserID == user.ID).ToListAsync(); var newItems = GetDifference(items, currentItems); newItems.ForEach(x => x.UserID = user.ID); db.RemoveRange(currentItems); db.AddRange(newItems); await db.SaveChangesAsync(); } }