不眠等待？

Question

我想做的是启动一个函数，然后将 bool 更改为 false，稍等片刻，然后再次将其变为 true。但是我想在函数不必等待的情况下执行此操作，我该怎么做？

我只能使用 Visual C# 2010 Express。

这是有问题的代码。我正在尝试接收用户输入（例如向右箭头）并相应地移动，但在角色移动时不允许进一步输入。

        x = Test.Location.X;
        y = Test.Location.Y;
        if (direction == "right") 
        {
            for (int i = 0; i < 32; i++)
            {
                x++;
                Test.Location = new Point(x, y);
                Thread.Sleep(31);
            }
        }
    }

    private void Form1_KeyDown(object sender, KeyEventArgs e)
    {
        int xmax = Screen.PrimaryScreen.Bounds.Width - 32;
        int ymax = Screen.PrimaryScreen.Bounds.Height - 32;
        if (e.KeyCode == Keys.Right && x < xmax) direction = "right";
        else if (e.KeyCode == Keys.Left && x > 0) direction = "left";
        else if (e.KeyCode == Keys.Up && y > 0) direction = "up";
        else if (e.KeyCode == Keys.Down && y < ymax) direction = "down";

        if (moveAllowed)
        {
            moveAllowed = false;
            Movement();
        }
        moveAllowed = true;  
    }

Answer 1

使用Task.Delay:

Task.Delay(1000).ContinueWith((t) => Console.WriteLine("I'm done"));

或

await Task.Delay(1000);
Console.WriteLine("I'm done");

对于较旧的框架，您可以使用以下内容：

var timer = new System.Timers.Timer(1000);
timer.Elapsed += delegate { Console.WriteLine("I'm done"); };
timer.AutoReset = false;
timer.Start();

根据问题中的描述举例：

class SimpleClass
{
    public bool Flag { get; set; }

    public void function()
    {
        Flag = false;
        var timer = new System.Timers.Timer(1000);
        timer.Elapsed += (src, args) => { Flag = true; Console.WriteLine("I'm done"); };
        timer.AutoReset = false;
        timer.Start();
    }
}

Answer 2

我意识到答案已经被接受，我喜欢 ixSci 的答案，他建议使用 Timer 对象来实现 OP 的目标。

但是，使用 System.Timers.Timer 特别引入了线程注意事项。为了确保这种情况下的正确性，需要更多代码来正确同步布尔标志值。基本上，在读取或写入标志的任何地方，代码区域都需要在其周围定义一个锁定语句。

它必须看起来像这样：

private final object flagLock = new object();
private bool moveAllowed = true;
private System.Timers.Timer timer = new System.Timers.Timer();

public Form1()
{
    this.timer.Interval = 1000;
    this.timer.AutoReset = false;
    this.timer.Elapsed += (s, e) =>
    {
        // this DOES NOT run on the UI thread, so locking IS necessary to ensure correct behavior.
        this.timer.Stop();
        lock (this.flagLock) {
            this.moveAllowed = true;
        }
    };
}

// The code in this event handler runs on the UI thread.
private void Form1_KeyDown(object sender, KeyEventArgs e)
{
    // Locking is necessary here too.
    lock (this.flagLock) {
        if (this.moveAllowed)
        {
            this.moveAllowed = false;
            Movement();
            this.timer.Start(); // wait 1 second to reset this.moveAllowed to true.
        }
    }
}

或者，为了避免考虑线程，也许 OP 可以考虑使用不同风格的 Timer class。即：System.Windows.Forms.Timer。这样，布尔标志在 UI 线程上将始终为 read/written，并且不需要任何类型的额外锁定来确保正确性。

在这种情况下，代码将如下所示：

private bool moveAllowed = true;
private System.Windows.Forms.Timer timer = new System.Windows.Forms.Timer();

public Form1()
{
    this.timer.Interval = 1000;
    this.timer.Tick += (s, e) =>
    {
        // this runs on the UI thread, so no locking necessary.
        this.timer.Stop(); // this call is necessary, because unlike System.Timers.Timer, there is no AutoReset property to do it automatically.
        this.moveAllowed = true;
    };
}

// The code in this event handler runs on the UI thread.
private void Form1_KeyDown(object sender, KeyEventArgs e)
{
    if (this.moveAllowed)
    {
        this.moveAllowed = false;
        Movement();
        this.timer.Start(); // wait 1 second to reset this.moveAllowed to true.
    }
}

不眠等待？

Waiting without Sleeping?

c#

function

wait