HtmlHelper extensions

HtmlHelperExtensions.cs

using System.Linq;
using System.Text;
using System.Text.RegularExpressions;

namespace System.Web.Mvc
{
    public static class HtmlHelperExtensions
    {
        #region HtmlHelper Extensions
        public static string Email(this HtmlHelper helper, string email, string message = "JavaScript is disabled, please enable to read this email address")
        {
            var regex = new Regex(@"^\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*$");

            if (!regex.Match(email).Success) return null;

            string[] parts = email.Split('@');
            string who = parts[0];
            string at = parts[1];

            var html = new StringBuilder();
            html.AppendFormat("<script>var who = '{0}', at = '{1}', e = who + '@' + at;document.write('<a href=\"mailto:'+e+'\">'+e+'</a>');</script>", who, at);
            html.AppendFormat("<noscript>{0}</noscript>", message);
            return html.ToString();
        }

        public static IHtmlString StripTags(this HtmlHelper helper, string value, params string[] tags)
        {
            string stripped = value;
            foreach (var tag in tags)
            {
                stripped = Regex.Replace(value, "<[^>]p*>", "", RegexOptions.Multiline | RegexOptions.IgnoreCase);
            }
            return new HtmlString(stripped);
        }

        public static string Tel(this HtmlHelper helper, string prefix, string number)
        {
            return prefix + " " + string.Join(" ", number.SplitParts(2));
        }

        /// <summary>
        /// Modified QueryString with key to value
        /// </summary>
        /// <param name="helper"></param>
        /// <param name="name"></param>
        /// <param name="value"></param>
        /// <returns>?key=value</returns>
        public static IHtmlString ModifyQueryString<T>(this HtmlHelper helper, string key, T value)
        {
            var request = HttpContext.Current.Request;
            var nameValues = HttpUtility.ParseQueryString(request.QueryString.ToString());
            nameValues.Set(key, value.ToString());
            return new HtmlString("?" + nameValues.ToString());
        }

        /// <summary>
        /// 
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="helper"></param>
        /// <param name="key">The key of the QueryString</param>
        /// <param name="fallback">If empty or null</param>
        /// <returns></returns>
        public static T ParseQueryString<T>(this HtmlHelper helper, string key, T fallback)
        {
            var request = HttpContext.Current.Request;
            var nameValues = HttpUtility.ParseQueryString(request.QueryString.ToString());
            if (nameValues.AllKeys.Contains(key))
            {
                try
                {
                    return (T)Convert.ChangeType(nameValues.Get(key), typeof(T));
                } catch (Exception) { }
            }
            return fallback;
        }
        #endregion
    }
}