DesktopHelper.Util.CheckUpdate.IsConnectedInternet C# (CSharp) Method

        public bool IsConnectedInternet()
        {
            int i = 0;
            if (InternetGetConnectedState(out i, 0))
            {
                //已联网
                return true;
            }
            else
            {
                //未联网
                return false;
            }
        }

 //检查更新
 private void UpdateToolStripMenuItem_Click(object sender, EventArgs e)
 {
     try
     {
         _checkUpdate = new CheckUpdate();
         if (_checkUpdate.IsConnectedInternet())
         {
             if (_checkUpdate.Download())
             {
                 if (_checkUpdate.HasNewVersion())
                 {
                     form_Update = UpdateForm.GetInstance(_checkUpdate.NewVersion);
                     form_Update.CloseHandlor += new UpdateForm.CloseHandler(CloseDeskHelper);
                     form_Update.ShowForm();
                 }
                 else//HasNewVersion()
                 {
                     MessageBox.Show("已经是最新版本");
                 }
             }
             else//Download()
             {
                 MessageBox.Show("已经是最新版本");
             }
         }
         else//IsConnectedInternet()
         {
             MessageBox.Show("本机没有连接互联网");
         }
     }
     catch (Exception ex)
     {
         log.WriteLog(ex.ToString());
     }
 }