Hi all,
   i found the solution for this.

we can use like this:

public bool IsValidEmail(string strIn)
{
   // Return true if strIn is in valid e-mail format.
   return Regex.IsMatch(strIn,
@"^([\w-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([\w-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$");
}

and we need to add the name space : system.text.regularexpressions;

this function will return wheather the given email address is valid or not.
Thanks to all.

Thanks & Regards,
Srinivasan.K