选择选项后自动售货机重复菜单

这是我的自动售货机。我现在需要能够在切换结束时重复菜单，以允许用户回到自动售货机或退出程序。

我会使用while循环或if/else语句吗?我尝试在while循环中嵌套整个东西，但随后它重复了purchase选项。

        int iNumCrisps = 10;
        int iCrispsBought;
        int iNumChocbars = 20;
        int iChocbarsBought;
        int iNumSweets = 30;
        int iSweetsBought;
        double dTotalMoney = 0;
        int iChoice;

        {
            //display the choices
            Console.WriteLine("Vending Machine");
            Console.WriteLine("1 - Buy chocbars");
            Console.WriteLine("2 - Buy crisps");
            Console.WriteLine("3 - Buy sweets");
            // get the users choice
            Console.Write("Enter your choice: ");
            iChoice = Convert.ToInt32(Console.ReadLine());
            //validate user input
            while (iChoice < 1 || iChoice > 3)
            {
                Console.Write("Incorrect option. Please Re-Enter: ");
                iChoice = Convert.ToInt32(Console.ReadLine());
            }

                switch (iChoice)
                {
                    case 1: //user has chosen chocbars
                        Console.WriteLine();
                        Console.Write("How many chocbars do you wish to purchase?");
                        iChocbarsBought = Convert.ToInt32(Console.ReadLine());
                        iNumChocbars = iNumChocbars - iChocbarsBought;
                        dTotalMoney = dTotalMoney + (iChocbarsBought * 0.25);
                        Console.WriteLine("There are now" + iNumChocbars + " chocbars in the machine");
                        break;
                    case 2: //User has chosen crisps
                        Console.WriteLine();
                        Console.Write("How many crisps do you wish to purchase?");
                        iCrispsBought = Convert.ToInt32(Console.ReadLine());
                        iNumCrisps = iNumCrisps - iCrispsBought;
                        dTotalMoney = dTotalMoney + (iCrispsBought * 0.30);
                        Console.WriteLine("There are now" + iNumCrisps + " crisps in the machine");
                        break;
                    case 3: //user has chosen sweets
                        Console.WriteLine();
                        Console.Write("How many sweets do you wish to purchase?");
                        iSweetsBought = Convert.ToInt32(Console.ReadLine());
                        iNumSweets = iNumSweets - iSweetsBought;
                        dTotalMoney = dTotalMoney + (iSweetsBought * 0.20);
                        Console.WriteLine("There are now " + iNumSweets + " sweets in the machine");
                        break;
                    default:
                        Console.WriteLine("You must enter a number from 1 to 3");
                        break;
                }// end switch

            //validate user input
            while (iChoice < 1 || iChoice > 3)
            {
                Console.Write("Incorrect option. Please Re-Enter: ");
                iChoice = Convert.ToInt32(Console.ReadLine());
            }

            Console.WriteLine("There is now" + dTotalMoney + "p in the machine");
            Console.WriteLine();
            Console.WriteLine("Press any key to close");
            Console.WriteLine();
            Console.ReadKey();
        }
    }
}

}