Paypal response.redirect

Hi all
I'm having some trouble integrating Paypal with my shopping cart in c#
What I have been trying to do is simply have a buy button that triggers a response.redirect to paypal, but for some reason the button simply doesn't do anything when clicked. 
My code behind is as follows:
public partial class MyShoppingCart : System.Web.UI.Page { protected void Paypalbutton_Click(object sender, EventArgs e) {
string amount_1 = string.Format("{0,19:C}", Profile.SCart.Total);
string Name = "Lance Nicholson";
string my_paypal_email = "EMAIL REMOVED";
string return_page = "notify.aspx"; string notify_page = "home.aspx"; string cancel_page = "logout.aspx";
string item_name = "Lance Nicholson";
string c ...