User.Identity.IsAuthenticated on a form

Hi everybody,

I'm trying to get a website that uses PayPal payment to use
"User.Identity.IsAuthenticated"


What I want is when people click on the buy now button it should ask them to
log in before it actually goes to the PayPal shopping cart.


My code:


protected void btn_LoginClick(object sender, EventArgs e)

    {

        if (User.Identity.IsAuthenticated ==
false)

        {

           
Server.Transfer("Account.aspx");

        }

    }


 


PayPal button:


<form target="paypal" action="https://www.paypal.com/cgi-bin/webscr"
method="post"  onclick="btn_LoginClick">

<input type="hidd ...