C#获取页面的HTML

public class HTMLHelper
...{
    私有字段#region 私有字段
     private static int currentTry = 0;
    private static string contentType = "application/x-www-form-urlencoded";
    private static int maxTry = 10;
    private static string accept = "image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-shockwave-flash, application/x-silverlight, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, application/x-ms-application, application/x-ms-xbap, application/vnd.ms-xpsdocument, application/xaml+xml, application/x-silverlight-2-b1, */*";
    private static string userAgent = "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; .NET CLR 2.0.50727; .NET CLR 3.0.04506.648; .NET CLR 3.5.21022)";
    private static Encoding encoding = Encoding.GetEncoding("utf-8");
    #endregion

    /**//// <summary>
    /// 获取HTML
    /// </summary>
    /// <param name="url">地址</param>
    /// <param name="postData">post 提交的字符串</param>
    /// <param name="isPost">是否是post</param>
    /// <param name="cookieContainer">CookieContainer</param>
    public static string GetHtml(string url, string postData, bool isPost, CookieContainer cookieContainer)
    ...{
        if (string.IsNullOrEmpty(postData)) return GetHtml(url, cookieContainer);
        Thread.Sleep(NetworkDelay);
        currentTry++;
        HttpWebRequest httpWebRequest = null;
        HttpWebResponse httpWebResponse = null;
        try
        ...{
            byte[] byteRequest = Encoding.Default.GetBytes(postData);
            httpWebRequest = (HttpWebRequest)HttpWebRequest.Create(url);
            httpWebRequest.CookieContainer = cookieContainer;
            httpWebRequest.ContentType = contentType;
            httpWebRequest.ServicePoint.ConnectionLimit = maxTry;
            httpWebRequest.Referer = url;
            httpWebRequest.Accept = accept;
            httpWebRequest.UserAgent = userAgent;
            httpWebRequest.Method = isPost ? "POST" : "GET";
            httpWebRequest.ContentLength = byteRequest.Length;
            Stream stream = httpWebRequest.GetRequestStream();
            stream.Write(byteRequest, 0, byteRequest.Length);
            stream.Close();
            httpWebResponse = (HttpWebResponse)httpWebRequest.GetResponse();
            Stream responseStream = httpWebResponse.GetResponseStream();
            StreamReader streamReader = new StreamReader(responseStream, encoding);
            string html = streamReader.ReadToEnd();
            streamReader.Close();
            responseStream.Close();
            currentTry = 0;
            httpWebRequest.Abort();
            httpWebResponse.Close();
            return html;
        }
        catch (Exception e)
        ...{
            if (currentTry <= maxTry) GetHtml(url, postData, isPost, cookieContainer);
            currentTry--;
            if (httpWebRequest != null)  httpWebRequest.Abort();
            if (httpWebResponse != null) httpWebResponse.Close();
            return string.Empty;
        }
    }

    /**//// <summary>
    /// 获取HTML
    /// </summary>
    /// <param name="url">地址</param>
    /// <param name="cookieContainer">CookieContainer</param>
    public static string GetHtml(string url, CookieContainer cookieContainer)
    ...{
        Thread.Sleep(NetworkDelay);
        currentTry++;
        HttpWebRequest httpWebRequest = null;
        HttpWebResponse httpWebResponse = null;
        try
        ...{
            httpWebRequest = (HttpWebRequest)HttpWebRequest.Create(url);
            httpWebRequest.CookieContainer = cookieContainer;
            httpWebRequest.ContentType = contentType;
            httpWebRequest.ServicePoint.ConnectionLimit = maxTry;
            httpWebRequest.Referer = url;
            httpWebRequest.Accept = accept;
            httpWebRequest.UserAgent = userAgent;
            httpWebRequest.Method = "GET";
            httpWebResponse = (HttpWebResponse)httpWebRequest.GetResponse();
            Stream responseStream = httpWebResponse.GetResponseStream();
            StreamReader streamReader = new StreamReader(responseStream, encoding);
            string html = streamReader.ReadToEnd();
            streamReader.Close();
            responseStream.Close();
            currentTry--;
            httpWebRequest.Abort();
            httpWebResponse.Close();
            return html;
        }
        catch (Exception e)
        ...{
            if (currentTry <= maxTry) GetHtml(url, cookieContainer);
            currentTry--;
            if (httpWebRequest != null)  httpWebRequest.Abort();
            if (httpWebResponse != null) httpWebResponse.Close();
            return string.Empty;
        }
    }
}