public async Task <List <string> > GetOrderValidationErrors() { AppUser user = await GetCurrentUser(); List <string> errors = new List <string>(); if (!user.AssertQuantityOfCart()) { errors.Add("Items you have added to your cart exceed the quantity that is available."); } if (!user.AssertBalanceExceedsCost()) { errors.Add("Your available balance is insufficient to make the current purchase."); } return(errors); }