Question

我想制作一个每5秒显示一个图像的程序，然后暂停1秒然后显示下一个。但是我有一个问题暂停图像。如果我有消息框代码，它会停止显示图像我必须按确定继续，但如果没有显示图像，它会跳转到最后一张图像。请帮助，我必须在我的代码中添加什么才能正常工作？

private void button1_Click(object sender, EventArgs e)
{
    string[] arr1 =
        new string[] { "water", "eat", "bath", "tv", "park", "sleep" };

    for (int i = 0; i < 6; i++)
    {
        button1.BackgroundImage = 
            (Image)Properties.Resources.ResourceManager.GetObject(arr1[i]);
        new SoundPlayer(Properties.Resources.nero).Play();
        MessageBox.Show(arr1[i].ToString());

        Thread.Sleep(5000);
    }
}

Answer 1

问题是UI线程没有机会更新显示。即：显示图像，但UI不会更新。

一个不那么好的黑客就是使用Application.DoEvents让UI更新自己：

for (int i = 0; i < 6; i++)
{
    button1.BackgroundImage = (Image)Properties.Resources.ResourceManager.GetObject(arr1[i]);
    Application.DoEvents();

    new SoundPlayer(Properties.Resources.nero).Play();

    Thread.Sleep(5000);
}

另一个（更清洁）解决方案是更改逻辑，以便在按下按钮时启动计时器，更改图片，每5秒运行一次。我假设您正在使用Windows窗体，因此您可以在表单上放置一个名为Timer的{{1}}，将事件处理程序附加到timer事件，然后使用这样：

Elapsed

在计时器事件中，请使用以下代码：

// These are instance members outside any methods!!
private int currentImageIndex = 0;
string[] arr1 = new string[] { "water", "eat", "bath", "tv", "park", "sleep" };

private void button1_Click(object sender, EventArgs e)
{
    // EDIT: As per comments changed to turn the button into a Start/Stop button.
    //       When the button is pressed and the timer is stopped, the timer is started,
    //       otherwise it is started.

    // Stop the timer if it runs already
    if (timer.Enabled)
    {
        timer.Stop();
    }

    // Start the timer if it was stopped
    else
    {
        // Make the timer start right away
        currentImageIndex = 0;
        timer.Interval = 1;

        // Start the timer
        timer.Start();
    }
}

Answer 2

最好的方法是与定时器控制一起使用。将计时器的间隔设置为1秒，但最初将其禁用。然后按下按钮代码只需启用计时器。

public partial class MyForm : Form
{
    private int ImagePosition = 0;
    private string[] arr1 = new string[] { "water", "eat", "bath", "tv", "park", "sleep" };

    private void button1_Click(object sender, EventArgs e)
    {
        ImagePosition = 0;
        RotateImage();
        Timer1.Start();      
    }

    private void RotateImage()
    {
        button1.BackgroundImage = 
        (Image)Properties.Resources.ResourceManager.GetObject(arr1[ImagePosition]);
        new SoundPlayer(Properties.Resources.nero).Play();
        ImagePosition++;
    }

    private void timer1_Tick(object sender, EventArgs e)
    {
        if (ImagePosition > 5)
        {
            timer1.Enabled = false;
            return;
        }

        RotateImage();
    }
}

使用c＃暂停图像

2 个答案: