用到正则表达式、HttpWebRequest的一些网络知识。看一下下边的例子、很简单啊。

　　　Regex regex;  
        string[] weather = new string[5];
        string content = "";
       
        Match mcTmp;
        Match mcCity;
        int k = 1;

        HttpWebResponse theResponse;
        WebRequest theRequest;

        theRequest = WebRequest.Create("http://weather.news.qq.com/inc/ss82.htm");
        try
        {
            theResponse = (HttpWebResponse)theRequest.GetResponse();

            using (System.IO.Stream sm = theResponse.GetResponseStream())
            {
                System.IO.StreamReader read = new System.IO.StreamReader(sm, Encoding.Default);
                content = read.ReadToEnd();
            }
        }
        catch (Exception)
        {
            content = "";
        }
    

        string parttenTmp = "<td height=\"23\" width=\"117\" background=\"/images/r_tembg5.gif\" align=\"center\">(?<item1>[^<]+)</td>";
        k = 1;
        regex = new Regex(parttenTmp, RegexOptions.Compiled | RegexOptions.IgnoreCase);
        for (mcTmp = regex.Match(content), k = 1; mcTmp.Success; mcTmp = mcTmp.NextMatch(), k++)
        {

            weather[0] = mcTmp.Groups["item1"].Value;
        }
        parttenTmp = "height=\"23\" align=\"center\">(?<item1>[^/]+)</td>";
        k = 1;
        regex = new Regex(parttenTmp, RegexOptions.Compiled | RegexOptions.IgnoreCase);
        for (mcTmp = regex.Match(content), k = 1; mcTmp.Success; mcTmp = mcTmp.NextMatch(), k++)
        {
            weather[k] = mcTmp.Groups["item1"].Value;
        }
        return weather;

这个是以前写的一个抓取天气预报的方法.你可以参考一下。