Check an E-mail address with VB.NET Regex

This is a VB.NET Function to Check an e-mail address with Regex...

Function CheckValidEmail(Optional ByVal inputEmail As String = Nothing) As Boolean
If inputEmail Is Nothing Then
Return (False)
End If
Dim strRegex As String = "^([a-zA-Z0-9_\-\.]+)@((\[[0-9]{1,3}" + "\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\" + ".)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$"
Dim re As Regex = New Regex(strRegex)
If re.IsMatch(inputEmail) Then
Return (True)
Else
Return (False)
End If

End Function