static string GetWeatherInfo(string s1, string s2)
        {
            string ResponseText;
            string text;
            int startIndex;
            int endIndex;
            Uri url = new Uri(@"http://firetear.com/weather/lvweather.aspx");
            HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
            HttpWebResponse res = (HttpWebResponse)req.GetResponse();
            req.Method = "Post";
            StreamReader ReaderText = new StreamReader(res.GetResponseStream(), Encoding.UTF8);
            ResponseText = ReaderText.ReadToEnd();
            res.Close();
            startIndex = ResponseText.IndexOf(s1) + s1.Length;
            endIndex = ResponseText.IndexOf(s2);
            text = ResponseText.Substring(startIndex, endIndex - startIndex);
            return text;
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            Label1.Text = GetWeatherInfo(@"g>", @"</");
            Label2.Text = GetWeatherInfo(@"天气:", @",紫");
        }