C#抓取网页数据 解析标题描述图片等信息 去除HTML标签

private static string GetPageData(string url)
{
    if (url == null || url.Trim() == "")
        return null;
    WebClient wc = new WebClient();
    wc.Credentials = CredentialCache.DefaultCredentials;
    Byte[] pageData = wc.DownloadData(url);
    return Encoding.Default.GetString(pageData);//.ASCII.GetString
}

Match TitleMatch = Regex.Match(strResponse, "<title>([^<]*)</title>", RegexOptions.IgnoreCase | RegexOptions.Multiline);
title = TitleMatch.Groups[1].Value;

Match Desc = Regex.Match(strResponse, "<meta name=\"DESCRIPTION\" content=\"([^<]*)\">", RegexOptions.IgnoreCase | RegexOptions.Multiline);
strdesc = Desc.Groups[1].Value;

public class HtmlHelper
{
    /// <summary>
    /// HTML中提取图片地址
    /// </summary>
    public static List<string> PickupImgUrl(string html)
    {
        Regex regImg = new Regex(@"<img\b[^<>]*?\bsrc[\s\t\r\n]*=[\s\t\r\n]*[""']?[\s\t\r\n]*(?<imgUrl>[^\s\t\r\n""'<>]*)[^<>]*?/?[\s\t\r\n]*>", RegexOptions.IgnoreCase);
        MatchCollection matches = regImg.Matches(html);
        List<string> lstImg = new List<string>();
        foreach (Match match in matches)
        {
            lstImg.Add(match.Groups["imgUrl"].Value);
        }
        return lstImg;
    }
    /// <summary>
    /// HTML中提取图片地址
    /// </summary>
    public static string PickupImgUrlFirst(string html)
    {
        List<string> lstImg = PickupImgUrl(html);
        return lstImg.Count == 0 ? string.Empty : lstImg[0];
    }
}

private string StripHtml(string strHtml)
{
    Regex objRegExp = new Regex("<(.|\n)+?>");
    string strOutput = objRegExp.Replace(strHtml, "");
    strOutput = strOutput.Replace("<", "<");
    strOutput = strOutput.Replace(">", ">");
    return strOutput;
}

//把所有空格变为一个空格
Regex r = new Regex(@"\s+");
wordsOnly = r.Replace(strResponse, " ");
wordsOnly.Trim();