WPF C# - 标准(非特权)用户无法访问 Web 客户端?

WPF C# - Standard (non - privilege) user not able to accss the webclient?

这是我用来检查互联网连接的代码。但它总是失败。这对我的管理员用户运行良好,但不适用于我创建的标准(非特权)用户。这里可能缺少什么..

if (!App.IsInternetConnected)
            {
                await Task.Factory.StartNew(() =>
                {
                    App.IsInternetConnected = Utils.IsInternetConnected();
                });
            }

            if (!App.IsInternetConnected)
            {
                App.ShowMessage("FeatureNotAvailable");
                LoginProgress.Visibility = System.Windows.Visibility.Hidden;
                return;
            }


 IsInternetConnected method is as below.

internal static bool IsInternetConnected()
    {
       try
        {
            WebClient webclient = new  WebClientPool().GetIdleWebClientObject();

            try
            {
            webclient.DownloadString("http://www.google.com");
            return true;
        }

    }
    catch (Exception)
    {
            return false;
    }
  }

GetIdleWebClientObject 如下

 [MethodImpl(MethodImplOptions.Synchronized)]
        public WebClient GetIdleWebClientObject()
        {
            foreach (WebClient item in WebClientItems)
            {
                if (!item.IsBusy )
                {
                    Log.Instance.WriteLine("reused webclient");
                    item.Headers.Clear();
                    return item;
                }
            }
            Log.Instance.WriteLine("new webclient");
            WebClient NewItem = new WebClient();
            NewItem.UseDefaultCredentials = true;
            //NewItem.Credentials = CredentialCache.DefaultNetworkCredentials;

            NewItem.Proxy = WebRequest.GetSystemWebProxy();
            WebClientItems.Add(NewItem);
            return NewItem;
        }

我的问题有点绕口,但可能对任何人都有帮助。 这条 Log.Instance.WriteLine("new webclient"); 行是在 C:\ 驱动器中创建和写入日志文件。不允许标准用户和抛出异常。 这导致我没有显示实际上不相关的互联网错误。