Unhandled exception in mscorlib

Question

Discovered WCF and consequently started exploring it. This is a C# console application. Code works fine except when I try to Withdraw. If I enter amount of wrong type it detects(catches), informs me of invalid input and sends me back to menu prompt. That's fine and dandy until I get to the part where I try to withdraw more dosh than I have(balance). Supposedly, I should've gotten message saying that I'm short on funds to withdraw so much. Instead I get this:

An unhandled exception of type 'System.FormatException' occurred in mscorlib.dll

Where did I go wrong?

Main

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ServiceModel;

namespace BankAccountClient
{
    class Program
    {
        static void Main(string[] args)
        {
            BankAccountClient.ServiceReference1.ServiceClient client = new ServiceReference1.ServiceClient();
            bool done = false;
            do
            {
                Console.WriteLine("Select one of the following:");
                Console.WriteLine("\t1 -- Withdraw");
                Console.WriteLine("\t2 -- Deposit");
                Console.WriteLine("\t3 -- Balance");
                Console.Write("Enter Your selection (0 to exit): ");
                string strSelection = Console.ReadLine();
                int iSel;
                try
                {
                    iSel = int.Parse(strSelection);
                }
                catch (FormatException)
                {
                    Console.WriteLine("\r\nWhat?\r\n");
                    continue;
                }
                Console.WriteLine("\nYou selected  " + iSel + "\n");
                switch (iSel)
                {
                    case 0:
                        done = true;
                        break;
                    case 1:
                        int balance = client.Balance();
                        int amount;

                        //WCF Withdraw
                        Console.Write("How much would you like to withdraw?: ");
                        try
                        {
                            amount = int.Parse(Console.ReadLine());
                        }
                        catch (FormatException)
                        {
                            Console.WriteLine("\r\nInvalid input. Must be an integer\r\n");
                            continue;
                        }
                        if (amount > balance)
                        {
                            Console.WriteLine(String.Format("\r\nNot enough funds to withdraw ${0}\r\n"), amount);
                            continue;
                        }
                        else
                            client.Withdraw(amount);
                        Console.WriteLine(String.Format("\nCurrent balance is ${0}\n", client.Balance()));
                        break;
                    case 2:
                        //WCF Deposit
                        Console.WriteLine("Deposit();");
                        break;
                    case 3:
                        //WCF Balance
                        Console.WriteLine(String.Format("Current balance is ${0}", client.Balance()));
                        break;
                    default:
                        Console.WriteLine("You selected an invalid number: {0}\r\n", iSel);
                        continue;
                }
                Console.WriteLine();
            } while (!done);

            Console.WriteLine("\nGoodbye!");
        }
    }
}

WCF Service(short)

public class Service : IService
{

    private static int balance;

    public void Withdraw(int value)
    {
        balance -= value;
    }

    public void Deposit(int value)
    {
        balance += value;
    }

    public int Balance()
    {
        return balance;
    }
}

Answer 1

You have put a parenthesis in the wrong place. Change your output to this:

Console.WriteLine(String.Format("\r\nNot enough funds to withdraw {0}\r\n", amount));

Answer 2

You need to move amount into the String.Format method on this line

Console.WriteLine(String.Format("\r\nNot enough funds to withdraw ${0}\r\n"), amount);

So

Console.WriteLine(String.Format("\r\nNot enough funds to withdraw ${0}\r\n", amount));