c# - 在 C# 中，如何防止 PreviewKeyDown 事件在特定代码完成之前被多次按下？

Question

我设置了一个相机应用程序，我的问题是人们可以多次按下按钮，导致脚本困惑:

private void mainWinForm_PreviewKeyDown_1(object sender, PreviewKeyDownEventArgs e) {
  if (e.KeyCode == Keys.Space) {
    var timer = new System.Timers.Timer(1000);
    int count = 0;
    timer.SynchronizingObject = this;
    timer.AutoReset = true;
    timer.Elapsed += delegate {
      count++;
      if (count == 1) {
        label1.Text = File.ReadAllText("Countdown_3.txt");
      }
      if (count == 3) {
        label1.Text = File.ReadAllText("Countdown_2.txt");
      }
      if (count == 5) {
        label1.Text = File.ReadAllText("Countdown_1.txt");
      }
      if (count == 7) {
        webcam.Stop();
        label1.Text = File.ReadAllText("ImageCapturedPlusFrozen.txt");
      }
      if (count == 9) {
        label1.Text = File.ReadAllText("IdleForPreview.txt");
        label1.Refresh();
        Directory.CreateDirectory(DateTime.Now.ToString("yyyy-MM-dd"));
        using (Bitmap bmp = new Bitmap(imgVideo.ClientSize.Width, imgVideo.ClientSize.Height)) {
          using (Graphics g = Graphics.FromImage(bmp)) {
            g.DrawImage(imgVideo.Image,
              new Rectangle(0, 0, bmp.Width, bmp.Height),
              new Rectangle(0, 0, imgVideo.Image.Width, imgVideo.Image.Height),
              GraphicsUnit.Pixel);
          }
          bmp.Save(DateTime.Now.ToString("yyyy-MM-dd") + "/ " + DateTime.Now.ToString("HH-mm-ss") + ".png", ImageFormat.Png);
        }
      }
      if (count == 20) {
        label1.Text = "Press Button to Start!";
        webcam.Start();
        timer.Stop();
      }
    };
    timer.Start();
  }
}

在计时器结束之前，我如何才能禁用按键？我试过 KeyPreview = false;但这行不通!

Answer 1

您可以添加一个 bool 标志来指示是否有工作正在完成。然后在按下键时检查该标志。

bool flag = false;

private void mainWinForm_PreviewKeyDown_1(object sender, PreviewKeyDownEventArgs e)
    {
        if (!flag)
        {

                flag = true;
                \\.....
                if (count == 20)
                {
                    \\.......
                    timer.Stop();
                    flag = false;
                }

            timer.Start();
        }
    }