public static bool isEmail(string inputEmail)
{
inputEmail = NulltoString(inputEmail);
string strRegex = @"^([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})(\\]?)$";
Regex re = new Regex(strRegex);
if (re.IsMatch(inputEmail))
return (true);
else
return (false);
}