Application.DoEvents
private void button1_Click(object sender, EventArgs e)
{
Application.DoEvents();
this.label1.Text = "步骤1";
Application.DoEvents();
System.Threading.Thread.Sleep(5000);
Application.DoEvents();
this.label1.Text = "步骤2";
Application.DoEvents();
System.Threading.Thread.Sleep(5000);
Application.DoEvents();
this.label1.Text = "步骤3";
Application.DoEvents();
System.Threading.Thread.Sleep(5000);
Application.DoEvents();
this.label1.Text = "完成";
Application.DoEvents();
}