validate an email address?

Question

how can I validate if the email address provided by the user does exists or not before proceeding to send an email using SmtpClient in C#?

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Jassim Rahma

Answer 1

http://www.codeproject.com/KB/validation/Valid_Email_Addresses.aspx

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Gaurav Khanna

Answer 2

Code snippet if the email address is like [e-mail]:

        

string pattern = @"[-a-zA-Z0-9+&@#/%?=~_|!:,.;]*[-a-zA-Z0-9+&@#/%=~_|].[-a-zA-Z0-9+&@#/%?=~_|!:,.;]*[-a-zA-Z0-9+&@#/%=~_|]@[-a-zA-Z0-9+&@#/%?=~_|!:,.;]*[-a-zA-Z0-9+&@#/%=~_|].[-a-zA-Z0-9+&@#/%?=~_|!:,.;]*[-a-zA-Z0-9+&@#/%=~_|]-[-a-zA-Z0-9+&@#/%?=~_|!:,.;]*[-a-zA-Z0-9+&@#/%=~_|].[-a-zA-Z0-9+&@#/%?=~_|!:,.;]*[-a-zA-Z0-9+&@#/%=~_|].com";

System.Text.RegularExpressions.Match match = System.Text.RegularExpressions.Regex.Match(editemail.Text.Trim(), pattern, System.Text.RegularExpressions.RegexOptions.IgnoreCase); 
 if (!match.Success) 
{
 MessageBox.Show("You must specify valid E-mail", this.vGlobalVariables.gProductVersion, MessageBoxButtons.OK, MessageBoxIcon.Warning); 
 this.editemail.Focus();}

 General regex pattern related to your requirement can be found in http://www.regular-expressions.info/email.html

Cheers:)
Mark as answer if it helps to solve your query

Answer 3

Hello Jassim,

in my company we use EmailVerify.NET (http://www.emailverify.net), a Microsoft .NET component which supports e-mail syntax checking, domain MX test and mailbox validation too.
E-mail validation up to the mailbox level is easy as writing the following code block:

var verifier = new EmailVerifier();
var result = verifier.Verify("[e-mail]", VerificationLevel.Mailbox);

if (result.IsSuccess)
{
   // Go on, send the message
}

Additional code samples can be found here.
From their home page:

EmailVerify.NET is a powerful .NET component which verifies email addresses using various techniques, including:

• Syntax verification, according to RFC 2821 and RFC 2822
• MX record lookup
• Disposable email address (DEA) validation
• SMTP availability check
• Mailbox existence check, with greylisting support
• Catch-all test

It is completely written in managed code (C#) and is compliant with the Common Language Specification (CLS), so it can be used with any other .NET language, including VB.NET, C++/CLI, J#, IronPython, IronRuby and F#.

The price for this component is very small (less than 50 bucks) and their support is one of the greatest I've ever found for a small software company like they are.
Hope this helps.