How can I validate an email address using the same method used by the DataAnnotations attribute DataType.EmailAddress?

Question

I am using MVC3 and in certain locations in the code I am using the System.ComponentModel.DataAnnotations.DataType.EmailAddress attribute and letting MVCs Model validation do the validation for me.

However, I would now like to validate an email address in a different section of code where I am not using a model. I would like to use the same method that is already being used by MVC, however I was unable to find any information on how to do so.

EDIT - Sorry if my question was unclear. I will attempt to clarify.

Here is a snippet from the RegisterModel that is included with the default MVC template:

    public class RegisterModel
    {
...

        [Required]
        [DataType(DataType.EmailAddress)]
        [DisplayName("Email address")]
        public string Email { get; set; }
...
     }

These attributes instruct mvcs model validation on how to validate this model.

However, I have a string that should contain an email address. I would like to validate the email address the same way that mvc is doing it.

string email = "noone@nowhere.com";
bool isValid = SomeMethodForValidatingTheEmailAddressTheSameWayMVCDoes(email);

if you provide some code to depict the scenario, it would be easier to answer — Muhammad Adeel Zahid, Jul 07 '11 at 18:54
*I would now like to validate an email address in a different section of code where I am not using a model*. Could you show this section of your code so that we can have a base for discussion? — Darin Dimitrov, Jul 07 '11 at 18:55

Can Gencer · Accepted Answer · 2011-07-07T19:42:56.343

As others have said, the DataType attribute doesn't actually do any validation. I would recommend you to look at Data Annotations Extensions which includes already written validation extensions for a variety of things, including Email.

It is also possible to do model validation on your full model explicitly: Manual Validation with Data Annotations.

If you want to do per attribute validation for a specific field/property, you can also look at the tests for DataAnnotationExtensions which should give you what you want:

[TestMethod]
public void IsValidTests()
{
    var attribute = new EmailAttribute();
    Assert.IsTrue(attribute.IsValid(null)); // Don't check for required
    Assert.IsTrue(attribute.IsValid("foo@bar.com"));
    ..
}

score 0 · Answer 2 · answered Jul 07 '11 at 19:18

Have a look at this blog post by Scott Guthrie, which shows how to implement validation of an email address using a custom attribute (based on the RegularExpressionAttribute).

You can reuse that logic if you need to validate the email address somewhere else.

score 0 · Answer 3 · edited May 23 '17 at 12:15

You may want to look at this question: Is the DataTypeAttribute validation working in MVC2?

To summarize, [DataType(DataType.EmailAddress)] doesn't actually validate anything, it just says "hey, this property is supposed to be an e-mail address". Methods like Html.DisplayFor() will check for this and render it as <a href="mailto:foo">foo</a>, but the IsValid() method is pretty much a simple return true;.

You'll have to roll your own code to actually perform validation. The question linked above has some sample code you can use as a starting point.

How can I validate an email address using the same method used by the DataAnnotations attribute DataType.EmailAddress?

3 Answers3