public static void Withdraw(string cardNumber, string pin, decimal amount)
{
var context = new AtmEntities();
using (TransactionScope scope =
new TransactionScope(TransactionScopeOption.Required,
new TransactionOptions { IsolationLevel = System.Transactions.IsolationLevel.RepeatableRead }))
{
var bankAccount = context.CardAccounts.FirstOrDefault(a => a.CardNumber == cardNumber && a.CardPIN == pin);
if (bankAccount == null)
{
throw new InvalidOperationException("Invalid card number or/and pin!");
}
if (bankAccount.CardCash < amount)
{
throw new InvalidOperationException("The account has not enough money to complete the operation!");
}
if (amount <= 0)
{
throw new InvalidOperationException("The amoutnt should be positive!");
}
bankAccount.CardCash -= amount;
Update(bankAccount, context);
AddTransactionHistoryRecord(bankAccount.CardNumber, DateTime.Now, amount, context);
context.SaveChanges();
scope.Complete();
}
}
private static void AddTransactionHistoryRecord(string cardNumber, DateTime transactionDate, decimal amount, AtmEntities context)
{
context.TransactionHistories.Add(new TransactionHistory
{
CardNumber = cardNumber,
TransactionDate = transactionDate,
Amount = amount
});
}
private static void Update(CardAccount account, AtmEntities context)
{
context.CardAccounts.AddOrUpdate(a => a.CardNumber, account);
}