C#实现一个矩形不断向下延伸完整源程序

private void Form1_Paint(object sender, PaintEventArgs e)
{
Graphics g = e.Graphics;
int second = DateTime.Now.Second;
SolidBrush brush = new SolidBrush(Color.Blue);
Pen pen = new Pen(Color.Blue);
g.FillRectangle(brush, 100, 20, 30, second );
}
private void timer1_Tick(object sender, EventArgs e)
{
this.Refresh();
}

//timer的Enabled属性为ture;

//设置窗体的doublebuffer为true

…………类似可以实现指针时钟动画，具体请到博客(http://download.csdn.net/user/shuanghusun)下载，包含部分源代码及.exe文件.