Question

这是一个游戏：用户可以将鼠标悬停在多个元素上，但只有当鼠标停留在500毫秒以上时才会调用一个函数。如果用户将鼠标移到另一个元素上，则从500ms开始倒计时重启。但是，如果用户点击项目倒计时，则会停止直到其他元素悬停。

这是我的尝试，但由于取消是异步的，因此无法重新启动BackgroundWorker。

public BackgroundWorker bw = new BackgroundWorker();
private void Element_MouseEnter(object sender, MouseEventArgs e)
{
  bw.DoWork += (snd, args) =>
  {
     int i = 500; //500ms
     while (i > 0)
     {
       if (bw.CancellationPending) break;
        Thread.Sleep(10);
        i = i - 10;
     }             
  };
  bw.RunWorkerCompleted += (snd, args) =>
  {
     RunSomething(); //500 ms are out, nothing was clicked
  }
  if (bw.IsBusy) bw.CancelAsync();
  bw.RunWorkerAsync();
}

private void Element_Clicked(object sender, MouseEventArgs e)
{
   bw.CancelAsync();
}

必须有更好的方法......

Answer 1

private CancellationTokenSource tokenSource;

private async void button1_MouseEnter(object sender, EventArgs e)
{
    if (tokenSource != null)
        tokenSource.Cancel();

    tokenSource = new CancellationTokenSource();
    try
    {
        await Task.Delay(500, tokenSource.Token);
        if (!tokenSource.IsCancellationRequested)
        {
            //
        }
    }
    catch (TaskCanceledException ex) { }
}

private void button1_Click(object sender, EventArgs e)
{
    tokenSource.Cancel();
}

等待500ms以便用户输入能够取消或重启

1 个答案: