for (int i = 1; i < 10000; i++)
{
this.label1.Text = i.ToString();
Application.DoEvents();
System.Threading.Thread.Sleep(1000);
}
动态跟踪循环体 避免“假死”

for (int i = 1; i < 10000; i++)
{
this.label1.Text = i.ToString();
Application.DoEvents();
System.Threading.Thread.Sleep(1000);
}