If you try and create a MailAddress object in .NET with an IDN domain, it will fail with a FormatException.
To fix this, I have created two small helper functions.
One that gets a MailAddress object that works both with non-IDN and IDN domain names.
The other uses that one to validate if an email address is valid.
This is pretty smart, since people have a tendency to validate email addresses using different regular expressions, and none of them really works in all cases.
So first - here is how to get an email address for both types of domains:
public static MailAddress GetMailAddress(string email, string name)
{
if (string.IsNullOrEmpty(email) || email.Contains(' ') || email.Count(c => c == '@') > 1)
{
return null;
}
try
{
return string.IsNullOrEmpty(name) ? new MailAddress(email) : new MailAddress(email, name);
}
catch (FormatException)
{
if (!email.Contains("@") || email.Count(c => c == '@') != 1)
{
return null;
}
string[] parts = email.Split('@');
try
{
IdnMapping mapping = new IdnMapping();
return string.IsNullOrEmpty(name) ?
new MailAddress(string.Concat(mapping.GetAscii(parts[0]), "@", mapping.GetAscii(parts[1]))) :
new MailAddress(string.Concat(mapping.GetAscii(parts[0]), "@", mapping.GetAscii(parts[1])), name);
}
catch (ArgumentException)
{
return null;
}
catch (FormatException)
{
return null;
}
}
}
And here is how to use it to validate email addresses:
public static bool ValidateEmailAddress(string email)
{
return GetMailAddress(email, string.Empty) != null;
}
This is smart, since we don't use any regular expressions for it, but just uses .NET's own implementation to validate addresses.
That is really it - and it works everywhere, not just in Sitecore :-)
