Use Multi Regular Expression For a Property

Hi,
I want get email or phone number in one textbox but how to set regular expression for
phone number and email together ?

 [RegularExpression(@"^([a-zA-Z0-9_\-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$", ErrorMessage = "Please enter a valid e-mail adress")]
        [RegularExpression(@"^\(?([0-9]{4})\)?[-. ]?([0-9]{3})[-. ]?([0-9]{4})$", ErrorMessage = "incorect phone")]
        public string Username { get; set; }