public IActionResult CreateAccount(AccountsModel account) { Random rnd = new Random(); ulong rndNum; do { rndNum = 4000000000 + (ulong)rnd.Next(0, 999999999); }while (_service.IsAccountExist(rndNum.ToString())); account.AccountNumber = rndNum.ToString(); account.DateCreated = DateTime.Now.ToString("dd.MM.yyyy, HH:mm:ss"); account.Id = Guid.NewGuid(); if (_service.CreateAccount(account)) { return(Ok(account)); } return(BadRequest()); }