//添加文章过滤
    public string checkStr(string html)
    {
        System.Text.RegularExpressions.Regex regex1 =
            new System.Text.RegularExpressions.Regex(@"<script[\s\S]+</script *>",
                System.Text.RegularExpressions.RegexOptions.IgnoreCase);
        System.Text.RegularExpressions.Regex regex2 =
            new System.Text.RegularExpressions.Regex(@" href *= *[\s\S]*script *:",
                System.Text.RegularExpressions.RegexOptions.IgnoreCase);
        System.Text.RegularExpressions.Regex regex3 =
            new System.Text.RegularExpressions.Regex(@" no[\s\S]*=",
                System.Text.RegularExpressions.RegexOptions.IgnoreCase);
        System.Text.RegularExpressions.Regex regex4 =
            new System.Text.RegularExpressions.Regex(@"<iframe[\s\S]+</iframe *>",
                System.Text.RegularExpressions.RegexOptions.IgnoreCase);
        System.Text.RegularExpressions.Regex regex5 =
            new System.Text.RegularExpressions.Regex(@"<frameset[\s\S]+</frameset *>",
                System.Text.RegularExpressions.RegexOptions.IgnoreCase);
        System.Text.RegularExpressions.Regex regex6 =
                    new System.Text.RegularExpressions.Regex(@"\<img[^\>]+\>",
                        System.Text.RegularExpressions.RegexOptions.IgnoreCase);
        System.Text.RegularExpressions.Regex regex7 =
            new System.Text.RegularExpressions.Regex(@"</p>",
                System.Text.RegularExpressions.RegexOptions.IgnoreCase);
        System.Text.RegularExpressions.Regex regex8 =
            new System.Text.RegularExpressions.Regex(@"<p>",
                System.Text.RegularExpressions.RegexOptions.IgnoreCase);
        System.Text.RegularExpressions.Regex regex9 =
            new System.Text.RegularExpressions.Regex(@"<[^>]*>",
                System.Text.RegularExpressions.RegexOptions.IgnoreCase);
        html = regex1.Replace(html, ""); //过滤<script></script>标记
        html = regex2.Replace(html, ""); //过滤href=javascript: (<A>) 属性
        html = regex3.Replace(html, " _disibledevent="); //过滤其它控件的on...事件
        html = regex4.Replace(html, ""); //过滤iframe
        html = regex5.Replace(html, ""); //过滤frameset
        html = regex6.Replace(html, ""); //过滤frameset
        html = regex7.Replace(html, ""); //过滤frameset
        html = regex8.Replace(html, ""); //过滤frameset
        html = regex9.Replace(html, "");
        html = html.Replace(" ", "");
        html = html.Replace("</strong>", "");
        html = html.Replace("<strong>", "");
        return html;
    }
文章来自学IT网：http://www.xueit.com/html/2008-11/117_4433_00.html