Problem
I use this
@"^([\w\.\-]+)@([\w\-]+)((\.(\w){2,3})+)$"
To validate the email, use regexp.
This is for the first-level domain ([w.-]+) (many letters and numbers, also point and hyphen) This is for second-level domains ([w-]+). ((\.(\w){2,3})+) – and this is for other level domains (from 3 to infinity) with a point and two or three literals.
What is the issue with this regex?
EDIT: It doesn’t match the email address “something@someth.ing.”
Asked by Sergey
Solution #1
TLDs are similar to. There are a few more long TLDs that aren’t matched this way. Also, you can validate email addresses using the MailAddress class as Microsoft explains here in a note:
public bool IsValid(string emailaddress)
{
try
{
MailAddress m = new MailAddress(emailaddress);
return true;
}
catch (FormatException)
{
return false;
}
}
Because you don’t have to create (or try to comprehend) regex, this saves you a lot of time and effort.
EDIT: If you’re allergic to try/catch, here’s what you should do. You can use MailAddress in.NET 5. TryCreate. Also see https://stackoverflow.com/a/68198658 for an example of how to repair.., spaces, missing.TLDs, and other issues.
Answered by Alex
Solution #2
@”([w.-]+)@([w.-]+)((.(w)2,3)+)$” should work, in my opinion. You must write it as follows:
string email = txtemail.Text;
Regex regex = new Regex(@"^([\w\.\-]+)@([\w\-]+)((\.(\w){2,3})+)$");
Match match = regex.Match(email);
if (match.Success)
Response.Write(email + " is correct");
else
Response.Write(email + " is incorrect");
You should be aware that this will fail if:
Answered by Avinash
Solution #3
I have a phrase that I use to check email addresses.
I figured I’d write it here because none of the others were as concise or precise as mine.
@"^[\w!#$%&'*+\-/=?\^_`{|}~]+(\.[\w!#$%&'*+\-/=?\^_`{|}~]+)*"
+ "@"
+ @"((([\-\w]+\.)+[a-zA-Z]{2,4})|(([0-9]{1,3}\.){3}[0-9]{1,3}))$";
More information can be found here: Email Regular Expressions in C#
Also, this only tests for RFC validity based on email syntax, not whether the email existed in the first place. The only method to ensure that an email is genuine is to send it and have the recipient confirm receipt by clicking a link or entering a code.
Then there are domains like Mailinator.com and others that are just for fun. This has no effect on determining whether or not an email is from a disposable domain.
Answered by Rhyous
Solution #4
For it, I discovered a useful document on MSDN.
http://msdn.microsoft.com/en-us/library/01escwtf.aspx How to: Verify that Strings Are in Valid Email Format (Note that this code also allows non-ASCII characters to be used in Internet domain names.)
There are two implementations available: one for.Net 2.0/3.0 and the other for.Net 3.5 and higher. The 2.0/3.0 version is as follows:
bool IsValidEmail(string strIn)
{
// Return true if strIn is in valid e-mail format.
return Regex.IsMatch(strIn, @"^([\w-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([\w-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$");
}
The following are the results of my tests using this method:
Invalid: @majjf.com
Invalid: A@b@c@example.com
Invalid: Abc.example.com
Valid: j..s@proseware.com
Valid: j.@server1.proseware.com
Invalid: js*@proseware.com
Invalid: js@proseware..com
Valid: ma...ma@jjf.co
Valid: ma.@jjf.com
Invalid: ma@@jjf.com
Invalid: ma@jjf.
Invalid: ma@jjf..com
Invalid: ma@jjf.c
Invalid: ma_@jjf
Invalid: ma_@jjf.
Valid: ma_@jjf.com
Invalid: -------
Valid: 12@hostname.com
Valid: d.j@server1.proseware.com
Valid: david.jones@proseware.com
Valid: j.s@server1.proseware.com
Invalid: j@proseware.com9
Valid: j_9@[129.126.118.1]
Valid: jones@ms1.proseware.com
Invalid: js#internal@proseware.com
Invalid: js@proseware.com9
Invalid: js@proseware.com9
Valid: m.a@hostname.co
Valid: m_a1a@hostname.com
Valid: ma.h.saraf.onemore@hostname.com.edu
Valid: ma@hostname.com
Invalid: ma@hostname.comcom
Invalid: MA@hostname.coMCom
Valid: ma12@hostname.com
Valid: ma-a.aa@hostname.com.edu
Valid: ma-a@hostname.com
Valid: ma-a@hostname.com.edu
Valid: ma-a@1hostname.com
Valid: ma.a@1hostname.com
Valid: ma@1hostname.com
Answered by mr.baby123
Solution #5
The code below is based on Microsoft’s Data annotations implementation on github, and I believe it provides the most comprehensive email validation:
public static Regex EmailValidation()
{
const string pattern = @"^((([a-z]|\d|[!#\$%&'\*\+\-\/=\?\^_`{\|}~]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])+(\.([a-z]|\d|[!#\$%&'\*\+\-\/=\?\^_`{\|}~]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])+)*)|((\x22)((((\x20|\x09)*(\x0d\x0a))?(\x20|\x09)+)?(([\x01-\x08\x0b\x0c\x0e-\x1f\x7f]|\x21|[\x23-\x5b]|[\x5d-\x7e]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(\\([\x01-\x09\x0b\x0c\x0d-\x7f]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]))))*(((\x20|\x09)*(\x0d\x0a))?(\x20|\x09)+)?(\x22)))@((([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])*([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])))\.)+(([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])*([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])))\.?$";
const RegexOptions options = RegexOptions.Compiled | RegexOptions.IgnoreCase | RegexOptions.ExplicitCapture;
// Set explicit regex match timeout, sufficient enough for email parsing
// Unless the global REGEX_DEFAULT_MATCH_TIMEOUT is already set
TimeSpan matchTimeout = TimeSpan.FromSeconds(2);
try
{
if (AppDomain.CurrentDomain.GetData("REGEX_DEFAULT_MATCH_TIMEOUT") == null)
{
return new Regex(pattern, options, matchTimeout);
}
}
catch
{
// Fallback on error
}
// Legacy fallback (without explicit match timeout)
return new Regex(pattern, options);
}
Answered by CodeArtist
Post is based on https://stackoverflow.com/questions/5342375/regex-email-validation