ASP.NET email validator regex

Does anyone know what the regex used by the email validator in ASP.NET is?

Answers:

Thank you for visiting the Q&A section on Magenaut. Please note that all the answers may not help you solve the issue immediately. So please treat them as advisements. If you found the post helpful (or not), leave a comment & I’ll get back to you as soon as possible.

Method 1

Here is the regex for the Internet Email Address using the RegularExpressionValidator in .NET

w+([-+.']w+)*@w+([-.]w+)*.w+([-.]w+)*

By the way if you put a RegularExpressionValidator on the page and go to the design view there is a ValidationExpression field that you can use to choose from a list of expressions provided by .NET. Once you choose the expression you want there is a Validation expression: textbox that holds the regex used for the validator

Method 2

I don’t validate email address format anymore (Ok I check to make sure there is an at sign and a period after that). The reason for this is what says the correctly formatted address is even their email? You should be sending them an email and asking them to click a link or verify a code. This is the only real way to validate an email address is valid and that a person is actually able to recieve email.

Method 3

E-mail addresses are very difficult to verify correctly with a mere regex. Here is a pretty scary regex that supposedly implements RFC822, chapter 6, the specification of valid e-mail addresses.

Not really an answer, but maybe related to what you’re trying to accomplish.

Method 4

We can use RegularExpressionValidator to validate email address format. You need to specify the regular expression in ValidationExpression property of RegularExpressionValidator. So it will look like

 <asp:RegularExpressionValidator ID="validateEmail"    
  runat="server" ErrorMessage="Invalid email."
  ControlToValidate="txtEmail" 
  ValidationExpression="^([w.-]+)@([w-]+)((.(w){2,3})+)$" />

Also in event handler of button or link you need to check !Page.IsValid.
Check sample code here : sample code

Also if you don’t want to use RegularExpressionValidator you can write simple validate method and in that method usinf RegEx class of System.Text.RegularExpressions namespace.

Check example:

example

Method 5

For regex, I first look at this web site: RegExLib.com

Method 6

Apart from the client side validation with a Validator, I also recommend doing server side validation as well.

bool isValidEmail(string input)
{
    try
    {
        var email = new System.Net.Mail.MailAddress(input);
        return true;
    }
    catch
    {
        return false;
    }
}

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0