谁能给我一个进度条的例子？
想做个进度条，搞了半天学不会。

下面这个学习是我希望让进度条load30秒，这30秒内重复做一件事情，直到完成，则进度条结束。但是不行~谁教教我怎么搞？

private   void   MainForm_Shown(object   sender,   EventArgs   e)
{
          prgBar.Minimum   =   1;
          prgBar.Maximum   =   30;
          prgBar.Value   =   1;
          prgBar.Step   =   1;

          DateTime   dtStart   =   DateTime.Now;
          DateTime   dtEnd   =   new   DateTime(Convert.ToInt64(dtStart.Second   +   30));

          while   (DateTime.Now   !=   dtEnd)
          {
                  prgBar.PerformStep();
          }
}

------解决方案--------------------
private void button4_Click(object sender, EventArgs e)
{
progressBar1.Minimum = 0;
progressBar1.Maximum = 30;
progressBar1.Step = 1;
for (int i = 0; i < 30; i++)
{
System.Threading.Thread.Sleep(1000);
progressBar1.PerformStep();
}
}
------解决方案--------------------
private void Form1_Shown(object sender, EventArgs e)
{
prgBar.Minimum = 1;
prgBar.Maximum = 30;
prgBar.Value = 1;
prgBar.Step = 1;

DateTime dtEnd = DateTime.Now.AddSeconds(30);

while (DateTime.Now <= dtEnd)
{
TimeSpan vTimeSpan = new TimeSpan(dtEnd.Ticks - DateTime.Now.Ticks);
Application.DoEvents();
}
}