using System.Text.RegularExpressions;


        public bool IsEmailAdress(String emailAdress)
        {
            string MailAdressFormat = @"\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*";
            Regex regEx = new Regex(MailAdressFormat);
            return regEx.IsMatch(emailAdress);
        }
        public bool IsDate(String strDate)
        {
            Regex objAlphaPattern = new Regex(@"(^|\s|\()((([1-9]){1}|([0][1-9]){1}|
([1][012]){1}){1}[\/-]((2[0-9]){1}|(3[01]){1}|([01][1-9]){1}|([1-9]){1}){1}[\/-](((19|20)(
[0-9][0-9]){1}|([0-9][0-9]){1})){1}(([\s|\)|:])|(^|\s|\()((([0-9]){1}|([0][1-9]){1}|([1][0
12]){1}){1}[\/-](([11-31]){1}|([01][1-9]){1}|([1-9]){1}){1}[\/-](((19|20)([0-9][0-9]){1}|(
[0-9][0-9]){1})){1}(([\s|\)|:|$|\>])){1}){1}){1}){1}");
            return !objAlphaPattern.IsMatch(strDate);
        }

http://regexlib.com/DisplayPatterns.aspx adresinden yüzlece regex örnegi bulabilirsini.