CODEWITHSUNDEEP
c#regexwindows-phone-8windows-phone-8.1email-validation
alfah
alfah

Reputation: 2085

Regular expression check for email ID fails

I got this regex check for Email ID from MSDN. But it fails when _ and @ comes one after the other.

Expression:

 @"^(?("")("".+?(?<!\\)""@)|(([0-9a-z]((\.(?!\.))|[-!#\$%&'\*\+/=\?\^`\{\}\|~\w])*)(?<=[0-9a-z])@))" +
                @"(?(\[)(\[(\d{1,3}\.){3}\d{1,3}\])|(([0-9a-z][-\w]*[0-9a-z]*\.)+[a-z0-9][\-a-z0-9]{0,22}[a-z0-9]))$",

Example: [email protected] fails even though it is a valid ID.

Where do I need to alter the string, it looks really messy and I do not understand it.

Upvotes: 2

Views: 1003

Answers (5)

Arun Kumar
Arun Kumar

Reputation: 957

Yeah you are right it is not yet available in windows Phone 8. You can use something like below to validate email:

using System;
using System.Text.RegularExpressions;
public static bool IsValidEmail(string strIn)
{
   // Return true if strIn is in valid e-mail format.
      return Regex.IsMatch(strIn, 
      @"^[\w!#$%&'*+\-/=?\^_`{|}~]+(\.[\w!#$%&'*+\-/=?\^_`{|}~]+)*"
      + "@"
      + @"((([\-\w]+\.)+[a-zA-Z]{2,4})|(([0-9]{1,3}\.){3}[0-9]{1,3}))$"); 
}

Upvotes: 0

Dev Try
Dev Try

Reputation: 211

You can use this : "\w+([-+.']\w+)@\w+([-.]\w+).\w+([-.]\w+)*". I hope this will work.

Upvotes: 0

Avinash Raj
Avinash Raj

Reputation: 174766

Change (?<=[0-9a-z])@ in your regex to (?<=[0-9a-z_])@

(?<=[0-9a-z])@ asserts that the match @ must be preceded by 0-9 or a-z.

So by adding _ inside the char class would also allow _ to be present before @.

Assertion only not enough, we have to add real chars (ie, the pattern which actually matches the underscore symbol). Don't worry, \w inside the char class which exists before lookbehind + @ will do it for you.

Upvotes: 4

coder3521
coder3521

Reputation: 2646

This is what i am using :

mRegex = new Regex(@"^([a-zA-Z0-9_\-])([a-zA-Z0-9_\-\.]*)@(\[((25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9][0-9]|[0-9])\.){3}|((([a-zA-Z0-9\-]+)\.)+))([a-zA-Z]{2,}|(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9][0-9]|[0-9])\])$");

It works fine

Upvotes: 1

Arun Kumar
Arun Kumar

Reputation: 957

It is because of this thing in your regex

    (?<=[0-9a-z])@

requires explicitly a letter or a digit before the "@".

It is better to use Microsoft EmailAddress Validation attribute to validate email address rather than Regex. Or use this function to validate email address on server side.

    public bool IsValid(string emailaddress)
      {
       try
    {
        MailAddress m = new MailAddress(emailaddress);

        return true;
    }
    catch (FormatException)
    {
        return false;
    }
}

Upvotes: 0

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