除去网站发布的危险内容和string的扩展

方法一是去掉发布信息过程中的空格、‘、换行符

public static string FromSafeHtmlString(this string input)
{
    StringBuilder sb = new StringBuilder();
    sb.Append(HttpContext.Current.Server.HtmlDecode(input));
    sb.Replace("<br/>", "\r\n");
    sb.Replace("&nbsp;", " ");
    sb.Replace("&#39;", "'");
    return sb.ToString();
}

方法二是直接移除掉相关的危险html，这个方法主要用于文本编辑器

public static string RemoveDangerHtml(this string input)
{
    input = Regex.Replace(input, "<html[^>]*?>.*?</html>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<html[^>]*?/>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<body[^>]*?>.*?</body>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<body[^>]*?/>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<meta[^>]*?>.*?</meta>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<meta[^>]*?/>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<frame[^>]*?>.*?</frame>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<frame[^>]*?/>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<frameset[^>]*?>.*?</frameset>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<frameset[^>]*?/>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<iframe[^>]*?>.*?</iframe>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<iframe[^>]*?/>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<layer[^>]*?>.*?</layer>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<layer[^>]*?/>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<ilayer[^>]*?>.*?</ilayer>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<ilayer[^>]*?/>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<applet[^>]*?>.*?</applet>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<applet[^>]*?/>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, @"<script(?:[^>]*?)>(?:[^<]*?)<\/script(?:[^>]*?)>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<script[^>]*?/>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<link[^>]*?>.*?</link>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<link[^>]*?/>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<style[^>]*?>.*?</style>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<style[^>]*?/>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<form[^>]*?>.*?</form>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<form[^>]*?/>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<input[^>]*?>.*?</input>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<input[^>]*?/>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<button[^>]*?>.*?</button>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<button[^>]*?/>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<textarea[^>]*?>.*?</textarea>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<textarea[^>]*?/>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<select[^>]*?>.*?</select>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "<select[^>]*?/>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "on[a-z]+?=\"[^\"]+\"", "", RegexOptions.Singleline | RegexOptions.IgnoreCase);
    input = Regex.Replace(input, "on[a-z]+?='[^']+'", "", RegexOptions.Singleline | RegexOptions.IgnoreCase);
    return input;
}

方法三是移除相关javascript内容

public static string RemoveHtmlScript(this string htmlString)
{
    htmlString = Regex.Replace(htmlString, @"<script[^>]*?>\s*.*\s*</script>", "", RegexOptions.IgnoreCase);
    htmlString = Regex.Replace(htmlString, @"<style([\s\S]*)</style>", "", RegexOptions.IgnoreCase);
    htmlString = Regex.Replace(htmlString, "<(.[^>]*)>", "", RegexOptions.IgnoreCase);
    htmlString = Regex.Replace(htmlString, @"([\r\n])[\s]+", "", RegexOptions.IgnoreCase);
    htmlString = Regex.Replace(htmlString, "-->", "", RegexOptions.IgnoreCase);
    htmlString = Regex.Replace(htmlString, "<!--.*", "", RegexOptions.IgnoreCase);
    htmlString = Regex.Replace(htmlString, "&(nbsp|#160);", "   ", RegexOptions.IgnoreCase);
    htmlString = Regex.Replace(htmlString, "&(iexcl|#161);", "\x00a1", RegexOptions.IgnoreCase);
    htmlString = Regex.Replace(htmlString, "&(cent|#162);", "\x00a2", RegexOptions.IgnoreCase);
    htmlString = Regex.Replace(htmlString, "&(pound|#163);", "\x00a3", RegexOptions.IgnoreCase);
    htmlString = Regex.Replace(htmlString, "&(copy|#169);", "\x00a9", RegexOptions.IgnoreCase);
    htmlString = Regex.Replace(htmlString, @"&#(\d+);", "", RegexOptions.IgnoreCase);
    htmlString.Replace("<", "");
    htmlString.Replace(">", "");
    htmlString.Replace("\r\n", "");
    return htmlString;
}

方法四是替换掉<、>、‘
public static string ToSafeHtmlString(this string input)
{
    if (string.IsNullOrEmpty(input))
    {
        return string.Empty;
    }
    StringBuilder sb = new StringBuilder();
    sb.Append(HttpContext.Current.Server.HtmlEncode(input));
    sb.Replace("\r\n", "<br/>");
    sb.Replace("   ", "&nbsp;");
    sb.Replace("\n", "<br/>");
    sb.Replace("'", "&#39;");
    return sb.ToString();
}
 
以上方法调用很简单，textbox.方法名（）就可已执行相应的操作。以上方法是扩展了string类