Dec 4, 2013
(2 votes)

Email validation attribute and support for IMetadataAware

In this blog post I will describe one new feature in EPiServer 7.5 as well as another feature that was actually removed in a last minute change (as well as describing how you can implement this yourself). The feature that was removed was an EPiServer attribute called EmailAttribute that could be applied to a string property to enable email validation. In code it would look like this:

public virtual string Email { get; set; }


The reason for us to remove this was that there actually exists such a attribute in the System.ComponentModel.DataAnnotations namespace in .NET 4.5 (well, actually it’s called EmailAddressAttribute so there was a slight naming difference). So to avoid confision, we have removed our attribute. Using the .NET attribute should work with the limitation that the validation will be done server side since we have not added logic to send settings to the client yet. If you want to use an attribute that has support for client side validation as well as the ability to add several comma-separated email addresses you can add your own attribute with the following code:

using System;
using System.Web.Mvc;
using System.ComponentModel.DataAnnotations;
using EPiServer.Framework.Localization;
namespace Samples
    [AttributeUsage(AttributeTargets.Property, AllowMultiple = false)]
    public class EmailAttribute : ValidationAttribute, IMetadataAware
        public void OnMetadataCreated(ModelMetadata metadata)
            var extendedMetadata = metadata as ExtendedMetadata;
            if (extendedMetadata == null)
            string emailRegexPattern = AllowMultiple ? Framework.Validator.MultipleEmailRegexString : Framework.Validator.EmailRegexString;
            extendedMetadata.EditorConfiguration["pattern"] = emailRegexPattern;
            extendedMetadata.EditorConfiguration["invalidMessage"] = LocalizationService.Current.GetString("/episerver/shell/ui/resources/JQueryValidate/email");
        public override string FormatErrorMessage(string name)
            return LocalizationService.Current.GetString("/episerver/shell/ui/resources/JQueryValidate/email");
        public override bool IsValid(object value)
            var stringValue = value as string;
            if (String.IsNullOrEmpty(stringValue))
                return true;
            if (AllowMultiple)
                return Framework.Validator.MultipleEmailRegex.IsMatch(stringValue);
                return Framework.Validator.EmailRegex.IsMatch(stringValue);
        public bool AllowMultiple { get; set; }


If you take a look at the class above, the class inherrits from ValidationAttribute and there are two methods that are overridden to implement server side validation: IsValid and FormatErrorMessage. This was possible in the EPiServer 7 release so nothing new here. What’s new, however, is the support in EPiServer for the IMetadataAware interface (from System.Web.Mvc). I’m very excited about this since it makes it possible to add attributes that can handle both client and server side validation in one class which should bring on possibilities to add lots of cool validation attributes. In the class above, we define the “pattern” setting which is used by the standard text editor to validate input against a regular expression.

Note that the class above is using a translation from the EPiServer resources files directly. This is not part of our supported API and might change without notice over time…

Dec 04, 2013


Petter Klang
Petter Klang Dec 19, 2013 12:03 PM

Thanks for sharing this. Will surely come in handy

Please login to comment.
Latest blogs
Preview multiple Visitor Groups directly while browsing your Optimizely site

Visitor groups are great - it's an easy way to add personalization towards market segments to your site. But it does come with it's own set of...

Allan Thraen | Sep 26, 2022 | Syndicated blog

The Report Center is finally back in Optimizely CMS 12

With Episerver.CMS.UI 12.12.0 the Report Center is finally re-introduced in the core product.

Tomas Hensrud Gulla | Sep 26, 2022 | Syndicated blog

Dynamic Route in ASP.NET Core When MapDynamicControllerRoute Does Not Work

Background Creating one of the add-on for Optimizely I had to deal with challenge to register dynamically route for the API controller. Dynamic rou...

valdis | Sep 25, 2022 | Syndicated blog

404 Error on Static Assets Within an Optimizely plugin

Background With the move to CMS 12 and .NET 5/6, developers are now able to build Plugins and Extensions using Razor Class Libraries (RCL).  These...

Mark Stott | Sep 23, 2022

How to bypass the content creation view in Optimizely

Something that has come up a couple of times in the last few year is feedback from content editors about the editing view that comes up when creati...

Ynze | Sep 23, 2022 | Syndicated blog

Welcome to Optimizely World's New Tech Video Portal

Optimizely, leader in the digital experience realm, has become a wealth of world class SaaS products including Web Experimentation, Full Stack, B2B...

The Developer Marketing Team of Optimizely | Sep 22, 2022