private void Withdraw(double amount)
 {
     if (amount < ATMSession.MIN_WITHDRAWAL_AMOUNT)
     {
         var result = WpfMessageBox.Show("Warning", "Minimum withdrawal amount is 100.", MessageBoxButton.OK, WpfMessageBox.MessageBoxImage.Warning, WpfMessageBox.MessageBoxType.Warning);
         if (result.Equals(MessageBoxResult.OK))
         {
             ATMSession.RestartSessionTimer();
             WithdrawAmountTextBox.SelectAll();
             WithdrawAmountTextBox.Focus();
         }
     }
     else if (amount % ATMSession.MULTIPLICATION_AMOUNT != 0)
     {
         var result = WpfMessageBox.Show("Warning", "Enter amount in multiplications of " + ATMSession.MULTIPLICATION_AMOUNT, MessageBoxButton.OK, WpfMessageBox.MessageBoxImage.Warning, WpfMessageBox.MessageBoxType.Warning);
         if (result.Equals(MessageBoxResult.OK))
         {
             ATMSession.RestartSessionTimer();
             WithdrawAmountTextBox.SelectAll();
             WithdrawAmountTextBox.Focus();
         }
     }
     else
     {
         var dResult = WpfMessageBox.Show("Receipt", "Do you want to print receipt?", MessageBoxButton.YesNo, WpfMessageBox.MessageBoxImage.Question);
         if (dResult.Equals(MessageBoxResult.Yes))
         {
             ATMSession.RestartSessionTimer();
             _canPrintReceipt = true;
         }
         else
         {
             ATMSession.RestartSessionTimer();
             _canPrintReceipt = false;
         }
         StartWithdrawing(amount);
     }
 }
        /// <summary>
        /// Start withdrawing
        /// </summary>
        private void StartWithdrawing(double amount)
        {
            ProgressPage progressPage = new ProgressPage();

            navigationService.Navigate(progressPage);
            var progressTimer = new DispatcherTimer {
                Interval = TimeSpan.FromMilliseconds(2000)
            };

            progressTimer.Start();
            progressTimer.Tick += (_sender, args) =>
            {
                DBHelper dBHelper = new DBHelper();
                User     user     = dBHelper.GetUser(ATMSession.AccountNo);
                transaction = new Transaction(user.User_Id, ATMSession.AccountNo, DateTime.Now, amount);
                ReturnResult transactionResult = dBHelper.Withdraw(transaction);

                if (transactionResult == ReturnResult.Success)
                {
                    ATMSession.RestartSessionTimer();
                    if (_canPrintReceipt)
                    {
                        CreateReceiptPDF();
                    }
                    TransactionSuccessMsg();
                }
                else if (transactionResult == ReturnResult.IsEmpty)
                {
                    var result = WpfMessageBox.Show("Warning", "Your account balance is Rs. 0.00", MessageBoxButton.OK, WpfMessageBox.MessageBoxImage.Warning, WpfMessageBox.MessageBoxType.Warning);
                    if (result.Equals(MessageBoxResult.OK))
                    {
                        ATMSession.RestartSessionTimer();
                        WithdrawAmountTextBox.SelectAll();
                        WithdrawAmountTextBox.Focus();
                    }
                }
                else if (transactionResult == ReturnResult.AmountIsGreater)
                {
                    var result = WpfMessageBox.Show("Warning", "Entered amount is greater than your account balance.", MessageBoxButton.OK, WpfMessageBox.MessageBoxImage.Warning, WpfMessageBox.MessageBoxType.Warning);
                    if (result.Equals(MessageBoxResult.OK))
                    {
                        ATMSession.RestartSessionTimer();
                        WithdrawAmountTextBox.SelectAll();
                        WithdrawAmountTextBox.Focus();
                    }
                }
                else
                {
                    var result = WpfMessageBox.Show("Error", "Withdrwal Error. Please contact your bank.", MessageBoxButton.OK, WpfMessageBox.MessageBoxImage.Error, WpfMessageBox.MessageBoxType.Error);
                    if (result.Equals(MessageBoxResult.OK))
                    {
                        ATMSession.RestartSessionTimer();
                        WithdrawAmountTextBox.SelectAll();
                        WithdrawAmountTextBox.Focus();
                    }
                }

                navigationService.GoBack();
                progressTimer.Stop();
                progressTimer = null;
            };
        }