public static void UploadDataInBackground2 (string address)
{
    WebClient client = new WebClient ();
    Uri uri = new Uri(address);
    string text = "Time = 12:00am temperature = 50";
    byte[] data = System.Text.Encoding.UTF8.GetBytes (text);
    string method = "POST";

    client.UploadDataCompleted += new UploadDataCompletedEventHandler (UploadDataCallback2);
    client.UploadDataAsync (uri, method, data);
}

private static void UploadDataCallback2 (Object sender, UploadDataCompletedEventArgs e)
{
    byte[] data = (byte[])e.Result;
    string reply = System.Text.Encoding.UTF8.GetString (data);

    Console.WriteLine (reply);
}