最小化或关闭窗体时，隐藏到系统托盘

protected override void OnClosing(CancelEventArgs e )
{
      this.WindowState = FormWindowState.Minimized;         //窗体状态最小化
      e.Cancel = true;                                      //取消该事件，即取消onClosing事件
}

private void contextMenuItemsClose_Click(object sender, System.EventArgs e)
{
      Application.Exit();     //notify控件的 ContextMenu 中要设置一个“关闭程序”的项目，否则无法退出
}


//监视窗体状态，当最小化时，到系统托盘
private void Form1_Resize(object sender,System.EventArgs e)  
{   
     if(this.WindowState == FormWindowState.Minimized){  
           this.Visible=false;   
           this.notifyIcon1.Visible   =   true;   
     }else {   
           this.Visible   =   true;   
           this.notifyIcon1.Visible   =   false;                                   
      }   
}