Question

我希望我的图片框每2秒更新一次字符串/文本（并删除旧文本）。我在这里制作了一些代码，但它没有显示任何内容：

namespace WindowsFormsApplication2

public partial class Form2 : Form
{
    public Form2()
    {
        InitializeComponent();

               }

    private void Form2_Load(object sender, EventArgs e)
    {

    }

    static System.Windows.Forms.Timer myTimer = new System.Windows.Forms.Timer();
    static bool exitFlag = false;

    private void TimerEventProcessor(Object myObject, EventArgs myEventArgs)
    {

        var image = new Bitmap(this.pictureBox1.Width, this.pictureBox1.Height);
        var font = new Font("TimesNewRoman", 30, FontStyle.Bold, GraphicsUnit.Pixel);
        var graphics = Graphics.FromImage(image);
        graphics.DrawString("Hi", font, Brushes.White, new Point(350, 0));
        this.pictureBox1.Image = image;

        System.Threading.Thread.Sleep(1000);
        pictureBox1.Invalidate();
        graphics.DrawString("Tell me your name...", font, Brushes.White, new Point(100, 0));
        this.pictureBox1.Image = image;
        this.pictureBox1.Update();
        this.pictureBox1.Refresh();

        //dialog box in here

    }
      public  int ActivateTimer()
 {
   myTimer.Tick += new EventHandler(TimerEventProcessor);
    myTimer.Interval = 1000;
    myTimer.Start();
    while (exitFlag == false)
     {
        Application.DoEvents();

   }
    return 0;

 }

Answer 1

除非在非常特殊的情况下，否则不要在计时器事件中进行任何睡眠并避免使用DoEvents（）。

Update（）和Refresh（）没用。

如果您确实需要在计时器事件中显示一个对话框，请在对话前禁用计时器并在之后启用它。

如果您需要Invalidate，请将其放在DrawString之后。

Answer 2

 private void ActivateTimer ( )
    {
        myTimer.Interval = 1000;
        myTimer.Enabled = true;
        myTimer.Tick += new EventHandler(TimerEventProcessor);
        myTimer.Start();
    }

    private void TimerEventProcessor(Object myObject, EventArgs myEventArgs)
    {

        var image = new Bitmap(this.pictureBox1.Width, this.pictureBox1.Height);
        var font = new Font("TimesNewRoman", 30, FontStyle.Bold, GraphicsUnit.Pixel);
        var graphics = Graphics.FromImage(image);
        graphics.DrawString("Hi", font, Brushes.White, new Point(350, 0));
        this.pictureBox1.Image = image;


        graphics.DrawString("Tell me your name...", font, Brushes.White, new Point(100, 0));
        this.pictureBox1.Image = image;



    }

更新图片框

2 个答案: