getPageFromURL(string url)

    public string getPageFromURL(string url)
    {
        string content = "";
        // Create a new HttpWebRequest object.Make sure that
        // a default proxy is set if you are behind a fure wall.
        //其中,HttpWebRequest实例不使用HttpWebRequest的构造函数来创建,二是使用WebRequest的Create方法来创建.
        HttpWebRequest myHttpWebRequest1 = (HttpWebRequest)WebRequest.Create(url);

        //不维持与服务器的请求状态
        myHttpWebRequest1.KeepAlive = false;
        //创建一个HttpWebRequest对象
        //Assign the response object of HttpWebRequest to a HttpWebResponse variable./
        HttpWebResponse myHttpWebResponse1;
        try
        {
            //根据微软MSDN上所说:"决不要直接创建HttpWebResponse的实例,要使用HttpWebRequest的GetResponse()方法返回的实例."具体的原因我也不清楚,可能HttpWebResponse类的构造函数中没有实现HttpWebResponse实例的代码吧.
            myHttpWebResponse1 = (HttpWebResponse)myHttpWebRequest1.GetResponse();
            //设置页面的编码模式
            System.Text.Encoding utf8 = System.Text.Encoding.UTF8;
            Stream streamResponse = myHttpWebResponse1.GetResponseStream();
            StreamReader streamRead = new StreamReader(streamResponse, utf8);

            Char[] readBuff = new Char[256];
            //这里使用了StreamReader的Read()方法,参数意指从0开始读取256个char到readByff中.
            //Read()方法返回值为指定的字符串数组,当达到文件或流的末尾使,方法返回0
            int count = streamRead.Read(readBuff, 0, 256);
            while (count > 0)
            {
                String outputData = new String(readBuff, 0, count);
                content += outputData;
                count = streamRead.Read(readBuff, 0, 256);
            }
            myHttpWebResponse1.Close();
            return (content);
        }
        catch (WebException ex)
        {
            content = "在请求URL为：" + url + "的页面时产生错误，错误信息为" + ex.ToString();
            return (content);
        }
    }