Question

当用户点击按钮时，我尝试在预设的时间内更改pictureBox的背景颜色。我尝试使用计时器，但我在另一个问题上看到了Stopwatch。问题是循环中的代码没有正常运行并且它一直在崩溃。我怎样才能使这个工作？代码

private void b_click(object sender, EventArgs e)
{
    Button button = sender as Button;
    Dictionary <Button, PictureBox> buttonDict= new Dictionary<Button, PictureBox>();
    //4 buttons
    buttonDict.Add(bRED, pbRED);
    buttonDict.Add(bBlue, pbBLUE);
    buttonDict.Add(bGREEN, pbGREEN);
    buttonDict.Add(bYELLOW, pbYELLOW);
    Stopwatch s = new Stopwatch();
    s.Start();
    while (s.Elapsed < TimeSpan.FromSeconds(0.5))
    {
        buttonDict[button].BackColor = Color.Black;
        label1.Text = "black";//This part does run
    }
    buttonDict[button].BackColor = Color.White; //the pictureBox does turn white
    s.Stop();
}

Answer 1

使用Timer代替秒表：

private void b_Click(object sender, EventArgs e)
{
  Button button = sender as Button;
  Dictionary<Button, PictureBox> buttonDict = new Dictionary<Button, PictureBox>();
  //4 buttons
  buttonDict.Add(bRED, pbRED);
  buttonDict.Add(bBlue, pbBLUE);
  buttonDict.Add(bGREEN, pbGREEN);
  buttonDict.Add(bYELLOW, pbYELLOW);
  Timer timer = new Timer();
  timer.Interval = 500;
  timer.Tick += (o, args) =>
  {
    buttonDict[button].BackColor = Color.White;
    timer.Stop();
    timer.Dispose();
  };
  buttonDict[button].BackColor = Color.Black;
  label1.Text = "black";
  timer.Start();
}

另一种可能性，使用Task.Run：

private void b_Click(object sender, EventArgs e)
{
  Button button = sender as Button;
  Dictionary<Button, PictureBox> buttonDict = new Dictionary<Button, PictureBox>();
  //4 buttons
  buttonDict.Add(bRED, pbRED);
  buttonDict.Add(bBlue, pbBLUE);
  buttonDict.Add(bGREEN, pbGREEN);
  buttonDict.Add(bYELLOW, pbYELLOW);
  buttonDict[button].BackColor = Color.Black;
  label1.Text = "black";
  Task.Run(() =>
  {
    Thread.Sleep(500);
    Invoke(new MethodInvoker(() =>
    {
      buttonDict[button].BackColor = Color.White;
    }));
  });
}

Answer 2

使用类似的东西：

    private void b_click(object sender, EventArgs e)
    {
        pictureBox1.BackColor = Color.Black; //First color
        new System.Threading.Tasks.Task(() => PictureBoxTimeoutt(1000)).Start(); //miliseconds until change
    }

    public void PictureBoxTimeout(int delay)
    {
        System.Threading.Thread.Sleep(delay);
        Invoke((MethodInvoker)delegate
        {
            pictureBox1.BackColor = Color.White; //Second color
        };
    }

将图片框背景颜色更改x个时间

2 个答案: