private void Form1_Load(object sender, EventArgs e)
{
  System.Timers.Timer t = new System.Timers.Timer(3000);
  t.Elapsed += new System.Timers.ElapsedEventHandler(OnTimedEvent);
  t.Enabled = true;
  t.AutoReset = false;
}

private delegate void SetVisibleCallback();
//在給label1.visible賦值的地方調(diào)用以下方法即可
private void SetVisible()
{
  // InvokeRequired需要比較調(diào)用線程ID和創(chuàng)建線程ID
  // 如果它們不相同則返回true
  if (this.label1.InvokeRequired)
  {
    SetVisibleCallback d = new SetVisibleCallback(SetPan);
    this.Invoke(d);
   }
   else
   {
    this.label1.Visible = false;
   }
}

private void OnTimedEvent(object sender, System.Timers.ElapsedEventArgs e)
{
  SetPan();
}

CheckForIllegalCrossThreadCalls = false;////避免跨線程的問題
label1.Visible = false;