问检查Xamarin iOS上是否有WIFI

EN

private bool CheckConnectivity()
    {
        var isConnected = CrossConnectivity.Current.IsConnected;
        return isConnected;
    }

    /// <summary>
    /// Gets the current SSID.
    /// </summary>
    /// <value>The current SSID.</value>
    public string CurrentSSID 
    {
        get
        {
            NSDictionary dict;
            var status = CaptiveNetwork.TryCopyCurrentNetworkInfo ("en0", out dict);
            if (status == StatusCode.NoKey)
            {
                return string.Empty;
            }

            var bssid = dict [CaptiveNetwork.NetworkInfoKeyBSSID];
            var ssid = dict [CaptiveNetwork.NetworkInfoKeySSID];
            var ssiddata = dict [CaptiveNetwork.NetworkInfoKeySSIDData];

            return ssid.ToString();
        }
    }

    /// <summary>
    /// The local WiFi connection status.
    /// </summary>
    /// <returns>
    /// The <see cref="NetworkStatus"/>.
    /// </returns>
    public static NetworkStatus LocalWifiConnectionStatus()
    {
        NetworkReachabilityFlags flags;
        return (!IsAdHocWiFiNetworkAvailable(out flags) || (flags & NetworkReachabilityFlags.IsDirect) == 0) ?
            NetworkStatus.NotReachable :
            NetworkStatus.ReachableViaWiFiNetwork;
    }

public NetworkState GetNetworkState()
{
    object ssid = null;
    NSDictionary dict = null;

    var status = CaptiveNetwork.TryCopyCurrentNetworkInfo("en0", out dict);
    if (status == StatusCode.OK)
        ssid = dict[CaptiveNetwork.NetworkInfoKeySSID];

    using (SystemConfiguration.NetworkReachability r = new NetworkReachability("www.appleiphonecell.com"))
    {
        NetworkReachabilityFlags flags;

        if (r.TryGetFlags(out flags))
        {
            if ((flags & NetworkReachabilityFlags.Reachable) != 0)
            {
                if (ssid != null && !string.IsNullOrEmpty(ssid.ToString()))
                    return NetworkState.Wifi;
                else
                    return NetworkState.Carrier;//we are not connected to wifi, but we can reach the site...
            }
        }
    }

    return NetworkState.None;
}