c# - 在 Enum C# 中使用 Switch 语句

Question

您好，我正在创建一个控制台应用程序，用户在其中输入月份的数字，该应用程序会计算出它是几月，并显示答案并显示该月的天数。当 switch 语句在 Main 方法中时我让它工作，但现在它显示错误的月份。我有以下代码:

namespace ConsoleCA2{

public enum Months
{
    January = 31,
    February = 28,
    March = 31,
    April = 30,
    May = 31,
    June = 30,
    July = 31,
    August = 31,
    September = 30,
    October = 31,
    November = 30,
    December = 31
};

public class Program
{
    public const string NEWLINE = "\n";     //constant for new line


    static void Main(string[] args)
    {
        try
        {

            //prompt user for month number.
            Console.Write("Enter a Number to find out what Month it is: ");

            //convert users answer to integer
            int userInput = Convert.ToInt16(Console.ReadLine());

            //declare and initalise
            int daysInMonth = 0;
            string answer = String.Empty;

            //call relevent calculation methods
            answer = DetermineMonth(userInput);
            daysInMonth = DetermineDaysInMonth(userInput);

            //Write users answer to screen
            Console.WriteLine(answer);

            //Prompt user, whether they want to know number of days in the
            //month
            Console.Write("Would you like to know the number of days in" +
                " {0}: ", answer);

            //assign users answer to variable
            string userAnswer = Console.ReadLine();

                //Output answer if needed.
                if (userAnswer == "yes".Trim().ToLower())
                {
                    Console.WriteLine("The number of days in {0} is: {1}", 
                        answer, daysInMonth.ToString());
                }
                else if (userAnswer == "no".Trim().ToLower())
                {
                    Console.WriteLine(NEWLINE);
                    Console.WriteLine("You answered No, Have a good day!");
                }
                else
                {
                    Console.WriteLine("Please answer yes or no.");
                }

            Console.Read(); //Pauses screen for user
        }
            //catch any errors.
        catch (Exception err)
        {
            Console.WriteLine("Error" + err.Message);
        }

    }


    /// <summary>
    /// Determines What month the use enters and returns string value
    /// </summary>
    /// <param name="userInput"></param>
    /// <returns>returns the month as string</returns>
    public static String DetermineMonth(int userInput)
    {
        switch (userInput)
        {
            case 1:
                return Months.January.ToString();
            case 2:
                return Months.February.ToString();
            case 3:
                return Months.March.ToString();
            case 4:
                return Months.April.ToString();
            case 5:
                return Months.May.ToString();
            case 6:
                return Months.June.ToString();
            case 7:
                return Months.July.ToString();
            case 8:
                return Months.August.ToString();
            case 9:
                return Months.September.ToString();
            case 10:
                return Months.October.ToString();
            case 11:
                return Months.November.ToString();
            case 12:
                return Months.December.ToString();
            default:
                return "Error";
        }



    }

    /// <summary>
    /// Determines how many days is in selected month as integer
    /// </summary>
    /// <param name="userInput"></param>
    /// <returns>returns how many days in month</returns>
    public static int DetermineDaysInMonth(int userInput)
    {
        switch (userInput)
        {
            case 1:
                return Convert.ToInt16(Months.January);
            case 2:
                return Convert.ToInt16(Months.February);
            case 3:
                return Convert.ToInt16(Months.March);
            case 4:
                return Convert.ToInt16(Months.April);
            case 5:
                return Convert.ToInt16(Months.May);
            case 6:
                return Convert.ToInt16(Months.June);
            case 7:
                return Convert.ToInt16(Months.July);
            case 8:
                return Convert.ToInt16(Months.August);
            case 9:
                return Convert.ToInt16(Months.September);
            case 10:
                return Convert.ToInt16(Months.October);
            case 11:
                return Convert.ToInt16(Months.November);
            case 12:
                return Convert.ToInt16(Months.December);
            default:
                return 0;
        }
    }

旧的 switch 语句是这样的:

        switch (userInput)
        {
        case 1:
            answer = Months.January.ToString();
            daysInMonth = Convert.ToInt16(Months.January);
            break;
        case 2:
            answer = Months.February.ToString();
            daysInMonth = Convert.ToInt16(Months.February);
            break;
        case 3:
            answer = Months.March.ToString();
            daysInMonth = Convert.ToInt16(Months.March);
            break;
        case 4:
            answer = Months.April.ToString();
            daysInMonth = Convert.ToInt16(Months.April);
            break;
        case 5:
            answer = Months.May.ToString();
            daysInMonth = Convert.ToInt16(Months.May);
            break;
        case 6:
            answer = Months.June.ToString();
            daysInMonth = Convert.ToInt16(Months.June);
            break;
        case 7:
            answer = Months.July.ToString();
            daysInMonth = Convert.ToInt16(Months.July);
            break;
        case 8:
            answer = Months.August.ToString();
            daysInMonth = Convert.ToInt16(Months.August);
            break;
        case 9:
            answer = Months.September.ToString();
            daysInMonth = Convert.ToInt16(Months.September);
            break;
        case 10:
            answer = Months.October.ToString();
            daysInMonth = Convert.ToInt16(Months.October);
            break;
        case 11:
            answer = Months.November.ToString();
            daysInMonth = Convert.ToInt16(Months.November);
            break;
        case 12:
            answer = Months.December.ToString();
            daysInMonth = Convert.ToInt16(Months.December);
            break;
        default:
            answer = "Error";
            break;
    }

在我更改为单独的方法之前一直有效，然后它从那里开始走下坡路。现在即使我把它放回去，它仍然会混淆月份？

很困惑:S

预先感谢您的帮助...如果您能理解困惑的代码:p

Answer 1

NET Framework 包含大量代码。有时很难找到需要的东西，但已经有东西的可能性很高。而且，虽然搜索需要时间，但这是一个值得的时间，因为您可以为自己提供对 future 工作有用的知识

CultureInfo.CurrentCulture.DayFormatInfo.MonthNames
DateTime.DaysInMonth

using System.Globalization;
static void Main(string[] args)
{
    Console.Write("Enter a Number to find out what Month it is: ");

    int userInput = Convert.ToInt16(Console.ReadLine());
    if(userInput > 0 && userInput < 13)
    {            
         string monthName = CultureInfo.CurrentCulture.DayTimeFormat.MonthNames[userInput-1];
         int daysInMonth = DateTime.DaysInMonth(2013, userInput);
         ......

    }
}

如果您还需要考虑闰年，您应该获得年份的输入，但这非常简单