//Email id
validation in code behind using regular expression:
using
System.Text.RegularExpressions;// for Regex
const string emailpattern = @"\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*";
if
(Regex.IsMatch(txtemail.Text.Trim(), emailpattern))
{
Label1.Text=”This is valid mail address”;
}