Question

我愚蠢地关闭了一个我认为最近回答过的问题，但我还遇到了另一个问题。

按下输入时，如果没有输入字符，我的代码会崩溃。有办法防止这种情况吗？如果用户输入错误的字符，则会显示错误消息，但如果在未输入任何输入的情况下按下输入，则会崩溃。

我收到的错误消息是未处理的类型＆＃39; System.FormatException＆＃39;发生在mscorlib.dll中附加信息：字符串必须只有一个字符长。

这是我的代码：

＆＃13;

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;


namespace computerPackage
{
    class Program

    {
        static void Main(string[] args)
        {
            char computerPackage;
            const decimal DELUXE_PACKAGE = 1500;
            const decimal SUPER_PACKAGE = 1700;
            Console.Write("Input the Computer Package D or S: ");
            computerPackage = Char.Parse(Console.ReadLine());
            computerPackage = Char.ToUpper(computerPackage);
            if (computerPackage == 'D')
            {
                Console.WriteLine("Cost of Deluxe Computer Package is " + DELUXE_PACKAGE.ToString("C"));
            }
            else if (computerPackage == 'S')
            {
                Console.WriteLine("Cost of Deluxe Computer Package is " +
                SUPER_PACKAGE.ToString("C"));
            }
            else
            {
                Console.WriteLine("Package D or S not entered");
            }
            Console.WriteLine("Press any key to continue...");
            Console.ReadKey();          // pause
        }
    }
}

＆＃13;

Answer 1

按Enter后没有任何字符，程序会尝试解析一个不可能的空字符串，并会给出异常。在解析之前创建检查

    static void Main(string[] args)
    {
        char computerPackage;
        const decimal DELUXE_PACKAGE = 1500;
        const decimal SUPER_PACKAGE = 1700;
        Console.Write("Input the Computer Package D or S: ");
        string inp = Console.ReadLine();
        if (inp.Length==1)
        {
            computerPackage = Char.Parse(inp);
            computerPackage = Char.ToUpper(computerPackage);
            if (computerPackage == 'D')
            {
                Console.WriteLine("Cost of Deluxe Computer Package is " + DELUXE_PACKAGE.ToString("C"));
            }
            else if (computerPackage == 'S')
            {
                Console.WriteLine("Cost of Deluxe Computer Package is " +
                SUPER_PACKAGE.ToString("C"));
            }
            else
            {
                Console.WriteLine("Package D or S not entered");
            }
            Console.WriteLine("Press any key to continue...");
            Console.ReadKey();
        }
        else
            {
                Console.WriteLine("Package D or S not entered");
            }
            Console.WriteLine("Press any key to continue...");
            Console.ReadKey();

    }

C＃按Enter键时出错 - 程序崩溃

1 个答案: