线程未按预期启动

Question

我正在尝试做一个测试，看看某人是否有某些技能。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication2
{
    class timerup
    {
        public bool timeup = false;
    }

    class Program
    {
        public static void timer()
        {
            for (int i = 1; i < 3; i++)
            {
                System.Threading.Thread.Sleep(1000);
                if (i == 5)
                {
                    object a;
                    a = true;
                    a = new timerup();
                    timerup ClassRef;
                    ClassRef = (timerup)a;
                    ClassRef.timeup = true;
                }
            }
        }

        static void Main(string[] args)
        {
            Console.Title = "The Secret Agent Test";
            Console.BackgroundColor = ConsoleColor.Black;
            Console.ForegroundColor = ConsoleColor.Green;
            Console.WriteLine("Welcome, agent. This is the test to see if\nyou are good enough to be a full member of the OT Secret Agency.");
            Console.WriteLine("Do you want to continue? [Y/N]");
            string cont = Console.ReadLine();
            if (cont == "y" || cont =="Y")
            {
                Console.Clear();
                Console.WriteLine("Let's continue the test.");
                Console.WriteLine("Crack the password:");
                Console.WriteLine("Username: IDIOT_NOOB1337\nPROFILE: Likes memes such as doge.\nIs an elitist (Over the things he likes)\nOnly uses the word idiot as an insult");
                Console.WriteLine("Password:");
                string pass1 = Console.ReadLine();
                if (pass1 == "AnyoneWhoDoesn'tLikeDogeIsAnIdiot" || pass1 == "anyonewhodoesn'tlikedogeisanidiot")
                {
                    Console.WriteLine("Account accessed.");
                    Console.WriteLine("Stage 1 Complete.");
                    Console.WriteLine("Loading next level...");
                    System.Threading.Thread.Sleep(2000);
                    Console.WriteLine("Level 2 loaded.");
                    System.Threading.Thread.Sleep(1000);
                    Console.Clear();
                    Console.WriteLine("Nice. You certainly have skill. But this test.... determines speed of mind.");
                    System.Threading.Thread.Sleep(2500);
                    Console.Clear();
                    Console.WriteLine("You only have two seconds to answer the next question. Press any key when ready.");
                    Console.ReadKey();
                    Console.Clear();
                    Console.WriteLine("What is 12x12?!"); // QUESTION
                    System.Threading.Thread t = new System.Threading.Thread(new System.Threading.ThreadStart(timer)); // SUCH COMPLEX CODE FOR A TIMER... WTF.
                    string product = Console.ReadLine();
                    object b;
                    b = true;
                    b = new timerup();
                    timerup ClassRef;
                    ClassRef = (timerup)b;
                    bool timerthing = ClassRef.timeup;
                    if (product != "144" || timerthing == true)
                    {
                        Console.WriteLine("Sorry, you are incorrect. Restart the test again.");
                        System.Threading.Thread.Sleep(2000);
                        Console.Clear();
                        System.Environment.Exit(-1);
                    }
                    else
                    {
                        Console.WriteLine("Impressive. Your mind is fast, too. Well, be prepared for the next test. Pressure.");
                    }
                }
            }
        }
    }
}

线程不执行；我怀疑这是因为 string product = Console.ReadLine(); 位。本次测验的第二题是 12x12，你有 2 秒的时间作答，除了计算这 2 秒的线程没有执行……为什么……？如果您知道，我该如何解决？

Answer 1

您只创建了一个话题。你也应该开始吧。

System.Threading.Thread t = new System.Threading.Thread(timer);
t.Start();

Answer 2

只是把这个写下来作为一个例子，说明如何在不使用线程的情况下检查已经过了多长时间。

        bool isInTime = false;

        var start = DateTime.Now;
        Console.WriteLine("answer this in 5 seconds, what is 2x2");
        var answer = Console.ReadLine();

        if ((DateTime.Now - start).TotalSeconds <= 5)
            isInTime = true;

        if (isInTime && answer == "4")
            Console.WriteLine("Good job you are now an agent");
        else
            Console.WriteLine("To slow and too dumb");

        Console.ReadKey();

秒表是另一种选择：http://www.dotnetperls.com/stopwatch

如果你真的想要线程（对于这个问题来说太过分了）这里有一些很好的例子：https://msdn.microsoft.com/en-us/library/ts553s52(v=vs.110).aspx

Answer 3

这两个答案是当场的，所以让我补充一下如何创建一个不那么复杂的计时器:)

var timeIsUp = false;
var timer = new Timer(_ => { timeIsUp = true; }, null, 5000, Timeout.Infinite);

但总的来说，@JensB 是绝对正确的 - 使用多线程应该是 last 选项。正确处理多线程非常困难，因此避免它是一个相当不错的策略。我展示的 Timer 示例也是多线程的 - 定时器的回调将发生在不同的线程上。这引入了同步问题，但对于像这样的简单情况，它们不应该太痛苦。要改进这一点，您至少要确保本地更新安全：

var syncObject = new object(); 
var timeIsUp = false;
var timer = new Timer(_ => { lock (syncObject) { timeIsUp = true; } }, null, 5000, 
                      Timeout.Infinite);

var answer = Console.ReadLine();

lock (syncObject)
{
  if (timeIsUp) ...
}

最后，如今完全没有必要手动使用 Thread。使用 Tasks 进行并发和多线程要容易得多。例如：

var timerTask = Task.Delay(5000);

var answer = Console.ReadLine();

if (timerTask.IsCompleted) Console.WriteLine("Too late");

IMO 的最佳选择是使用适当的异步 API - 遗憾的是，.NET Console class 没有这些。虽然很傻，但这似乎是一个相当不错的选择：

void Main()
{
    var cts = new CancellationTokenSource();
    cts.CancelAfter(TimeSpan.FromSeconds(2));

    var task = Task.Run(() => ReadLineFromConsole(cts.Token));
    task.Wait(cts.Token);

    if (task.IsCanceled)
    {
        Console.WriteLine("Too slow!");
        return;
    }

    var result = task.Result;

    if (result != "144")
    {
        Console.WriteLine("Wrong!");
        return;
    }

    // Continue
}

public string ReadLineFromConsole(CancellationToken token)
{  
    var buffer = new StringBuilder();
    int ch;

    while (!token.IsCancellationRequested)
    {
        Console.In.Peek();

        token.ThrowIfCancellationRequested();

        ch = Console.In.Read();
        if (ch == -1) return buffer.Length > 0 ? buffer.ToString() : null;

        if (ch == '\r' || ch == '\n') 
        {
            if (ch == '\r' && Console.In.Peek() == '\n') Console.In.Read();
            return buffer.ToString();
        }

        buffer.Append((char)ch);
    }

    token.ThrowIfCancellationRequested();

    // Shouldn't be reached, but the compiler doesn't know that.
    return null;
}

这种方法的有趣之处在于，即使用户没有按回车键，我也可以退出应用程序（并中止输入）。它还允许您使用 await 将复杂的工作流程联系在一起，尽管这在控制台应用程序中有点棘手。

辅助方法 ReadLineFromConsole 实际上与通常的 ReadLine 方法工作相同，但是，它还会检查取消，并防止它从以后的 "stealing" 数据中获取 ReadLine 调用，它会先 Peek 。这不会使其成为线程安全的——您仍然不应该同时从不同的线程使用多个 readlines。但这确实意味着我们可以在输出最终到来时忽略它。请记住，线程将一直等待，直到控制台输入到来 - 不要使用它来启动多个同时请求，除非确保最终有一些输入（例如，在 [ 之间使用通常的 Console.ReadLine =19=] 电话等）。

Answer 4

对您的代码进行一些重构并解决您的问题：

    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;
    using System.Threading;
    using System.Diagnostics;

namespace ConsoleApplication2
{
    class Program
    {
        static void WriteText(params string[] lines) { WriteText(0, lines); }

        static void WriteText(double delaySecs, params string[] lines)
        {

            for (int i = 0; i < lines.Length; i++) Console.WriteLine(lines[i]);
            if (delaySecs > 0) Thread.Sleep(TimeSpan.FromSeconds(delaySecs));
        }

        static void Main(string[] args)
        {
            Console.Title = "The Secret Agent Test";
            Console.ForegroundColor = ConsoleColor.Green;
            WriteText("Welcome, agent. This is the test to see if\nyou are good enough to be a full member of the OT Secret Agency.", "Do you want to continue? [Y/N]");
            var readk = Console.ReadKey();
            if (readk.Key == ConsoleKey.Y || readk.Key == ConsoleKey.N)
            {
                Console.Clear();
                WriteText("Let's continue the test.\n", "Crack the password:\n", "Username: IDIOT_NOOB1337\nPROFILE: Likes memes such as doge.",
                 "Is an elitist (Over the things he likes)", "Only uses the word idiot as an insult", "Password:");
                string pass1 = Console.ReadLine();

                if (pass1 != "AnyoneWhoDoesn'tLikeDogeIsAnIdiot" && pass1 != "anyonewhodoesn'tlikedogeisanidiot") return;

                WriteText(2, "Account accessed.", "Stage 1 Complete.", "Loading next level...");                
                WriteText(1, "Level 2 loaded.");                
                Console.Clear();
                WriteText(2.5, "Nice. You certainly have skill. But this test.... determines speed of mind.");                
                Console.Clear();
                Console.WriteLine("You only have two seconds to answer the next question. Press any key when ready.");
                Console.ReadKey();
                Console.Clear();
                Console.WriteLine("What is 12x12?!"); // QUESTION

                int allowedTime = 2 * 1000; // time allowed
                new Thread(() =>
                {
                    Stopwatch s = new Stopwatch();
                    s.Start();
                    while (s.ElapsedMilliseconds < allowedTime) { }
                    WriteText(2, "Sorry, you're too late. Restart the test again.");                    
                    Console.Clear();
                    Environment.Exit(-1);
                }).Start();

                string product = Console.ReadLine();
                if (product == "144") Console.WriteLine("Impressive. Your mind is fast, too. Well, be prepared for the next test. Pressure.");

                WriteText(2, "Sorry, you are incorrect. Restart the test again.");                
                Console.Clear();                
            }
        }
    }
}

线程未按预期启动

Threads do not start as expected

c#

multithreading

console-application