字符串“Sunday”未被识别为有效的布尔值答案

【问题标题】：String "Sunday" was not recognized as a valid Boolean字符串“Sunday”未被识别为有效的布尔值
【发布时间】：2022-01-25 21:15:03
【问题描述】：

在编程方面我是个初学者，所以对于这里的大多数人来说，我的问题可能看起来很容易。我正在尝试制作一个简单的程序，您可以在其中写下一周中的某一天，它应该根据答案显示信息。我选择星期天作为正确答案。我用 bool 和 string 进行了尝试，但我遇到了一个问题，它没有转换答案，所以我真的不知道下一步该做什么。这是代码。

        Boolean day;
        Boolean Sunday = true;
        Boolean Monday, Tuesday, Wednesday, Thursday, Friday, Saturday = false;

    

        Console.Write("What's the day of the week today? Write your answer here: ");
        day = Boolean.Parse(Console.ReadLine());

        if (Sunday == true)
        {
            Console.WriteLine("Your answer is correct!");
        }
        else
        {
            Console.WriteLine("Your answer is incorret. Please try again.");
        }


        Console.ReadKey();

【问题讨论】：

C# 无法将输入的字符串链接到某个变量的名称

标签： c# boolean

【解决方案1】：

您期望的用户输入是 string 的星期几，但您的数据类型是 Boolean，即 true 或 false。

因此，例如，当从“星期日”转换为用户输入时，代码会尝试转换为真或假并抛出异常。

你应该这样写你的程序：

private static void Main(string[] args)
{
    var currentDayOfWeek = DayOfWeek.Sunday;
    // currentDayOfWeek = DateTime.Today.DayOfWeek; // or if you want dynamically set todays day of week
    string userInputDayOfWeek;

    Console.Write("What's the day of the week today? Write your answer here: ");
    userInputDayOfWeek = Console.ReadLine();

    if ((Enum.TryParse(typeof(DayOfWeek), userInputDayOfWeek, ignoreCase: true, out object userInputParsed))
        && (DayOfWeek)userInputParsed == currentDayOfWeek)
    {
        Console.WriteLine("Your answer is correct!");
    }
    else
    {
        Console.WriteLine("Your answer is incorrect. Please try again.");
    }

    Console.ReadKey();
}

这里我们使用System命名空间中的枚举DayOfWeek，并使用忽略大小写标志解析用户输入。

【讨论】：

【解决方案2】：

据我了解，反射超出了您学校项目的范围，因此您可以创建一个字符串数组

    
    string trueDay = "Sunday";
    // or maybe better
      string trueDay=DateTime.Today.DayOfWeek.ToString();
    
    string[] falseDays = new string[] { "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"};


    Console.Write("What's the day of the week today? Write your answer here: ");
    var day = Console.ReadLine();

    if (day.ToLower() == trueDay.ToLower())
    {
        Console.WriteLine("Your answer is correct!");
    }
    else if ( falseDays.Any( d =>d.ToLower()==day.ToLower() ))
    {
                
        Console.WriteLine("Your answer is incorret. Please try again.");
        
    } else
        Console.WriteLine("Please type a correct day name!");


    Console.ReadKey();

如果 Linq 也不允许，试试这个

    var found=false;
    foreach (var item in falseDays)
    {
        if (item.ToLower() == day.ToLower())
        {  
            found=true;
            Console.WriteLine("Your answer is incorret. Please try again.");
            break;
        }
    }
     if(!found) Console.WriteLine("Please type a correct day name!");

【讨论】：