Question

如何在输出可用之前创建一个返回输出和块的自定义函数？我在想Console.ReadLine()之类的东西。像这样：

var resp = Output(); //blocks until output is sent.
...
//returns a string once SendOutput is called and hands over the string.
public static string Output() { /* what goes here? */ }
//Is this function even needed? Can I just fire Output somehow?
private static string SendOutput(string msg) { /* what goes here? */ }
...
//Calls sendoutput with the string to send.
SendOutput(msg);

基本上我正在制作一个被阻止的侦听器，直到它获取数据（就像调用console.readline一样），我需要内部代码来制作阻塞程序。

Answer 1

你想要的是阻塞方法调用在其他一些工作完成时发出信号。 ManualResetEvent是实现此行为的好方法;没有循环，一旦工作线程发出信号表明它已完成，返回几乎是瞬时的。

class Program
{
    static void Main(string[] args)
    {
        Blocker b = new Blocker();
        Console.WriteLine(b.WaitForResult());
    }
}

public class Blocker
{
    private const int TIMEOUT_MILLISECONDS = 5000;
    private ManualResetEvent manualResetEvent;

    private string output;

    public string WaitForResult()
    {
        // create an event which we can block on until signalled
        manualResetEvent = new ManualResetEvent(false);

        // start work in a new thread
        Thread t = new Thread(DoWork);
        t.Start();

        // block until either the DoWork method signals it is completed, or we timeout (timeout is optional)
        if (!manualResetEvent.WaitOne(TIMEOUT_MILLISECONDS))
            throw new TimeoutException();

        return output;
    }

    private void DoWork()
    {
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < 10; i++)
        {
            sb.AppendFormat("{0}.", i);
        }
        output = sb.ToString();

        // worker thread is done, we can let the WaitForResult method exit now
        manualResetEvent.Set();
    }
}

Answer 2

线程进程调用并使用后台工作程序在数据可用时通知回来。

private void Create_Thread()
{
    //Parameterized function
    Thread wt = new Thread(new ParameterizedThreadStart(this.DoWork));
    wt.Start([/*Pass parameters here*/]);
}

public void DoWork(object data)
{
    Thread.Sleep(1000);
    //Process Data - Do Work Here

    //Call Delegate Method to Process Result Data
    Post_Result(lvitem);
}

private delegate void _Post_Result(object data);

private void Post_Result(object data)
{
    //Process Result
}

如何使一个函数阻塞，直到它有数据在c＃中返回

2 个答案: