Regex for detecting emails in text
string sRegex = @"([w-]+(.[w-]+)*@([a-z0-9-]+(.[a-z0-9-]+)*?.[a-z]{2,6}|(d{1,3}.){3}d{1,3})(:d{4})?)";

Regex Regx = new Regex(sRegex, RegexOptions.IgnoreCase);

string sContent = "ttt <a href='mailto:[email protected]'>[email protected]</a> abc [email protected]";

"ttt <a href='mailto:[email protected]'>[email protected]</a> abc <a href='mailto:[email protected]'>[email protected]</a>";

[email protected]
[email protected]


public void Test()
{

    Regex pattern = new Regex(@"b(?<!mailto:)([w-]+(.[w-])*@([a-z0-9-]+(.[a-z0-9-]+)?.[a-z]{2,6}|(d{1,3}.){3}d{1,3})(:d{4})?)");
    MatchCollection matchCollection = pattern.Matches("ttt <a href='mailto:[email protected]'>[email protected]</a> abc [email protected]");
    foreach (Match match in matchCollection)
    {
        Debug.WriteLine(match);
    }
}

Regex pattern = new Regex(@"(?<!mailto:)b[w-]+@[a-z0-9-]+(.[a-z0-9-])*.[a-z]{2,8}b(?!</a)");
MatchCollection matchCollection = pattern.Matches("ttt <a href='mailto:[email protected]'>[email protected]</a> abc [email protected]");
foreach (Match match in matchCollection)
{
    Debug.WriteLine(match);
}