1.启用timer
2.form启动时即加载
private void Form1_Load(object sender, EventArgs e)
{
label1.Text = "☆★☆★☆★";
}
3.截取首位放到尾部，timer 1000毫秒内循环一次
private void timer1_Tick(object sender, EventArgs e)
{
label1.Text = label1.Text.Substring(1) + label1.Text.Substring(0, 1);
}