Parser Error Message: 'GarageManager.index' is not allowed here because it does not extend class 'System.Web.UI.Page'.!!

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

using System.Web.UI.HtmlControls;

using System.IO;

using GarageManager.Models;

namespace GarageManager.Pages
{
    public partial class Index : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            ProductModel model = new ProductModel();
            List<Product> products = model.GetAllProducts();

            if (products != null)
            {
                foreach (Product product in products)
                {
                    Panel productPanel = new Panel();
                    ImageButton imageButton = new ImageButton
                    {
                        ImageUrl = "~/Images/Products/" + product.Image,
                        CssClass = "productImage",
                        PostBackUrl = string.Format("~/Pages/Product.aspx?id={0}", product.Id)
                    };
                    Label lblName = new Label
                    {
                        Text = product.Name,
                        CssClass = "productName"
                    };
                    Label lblPrice = new Label
                    {
                        Text = "£ " + product.Price,
                        CssClass = "productPrice"
                    };

                    productPanel.Controls.Add(imageButton);
                    productPanel.Controls.Add(new Literal { Text = "<br/>" });
                    productPanel.Controls.Add(lblName);
                    productPanel.Controls.Add(new Literal { Text = "<br/>" });
                    productPanel.Controls.Add(lblPrice);

                    //Add dynamic controls to static control
                    pnlProducts.Controls.Add(productPanel);
                }
            }
             else
              pnlProducts.Controls.Add(new Literal { Text = "No products found!" });
        }
    }
}

<%@ Page Title="" Language="C#" MasterPageFile="~/MasterPage.Master" AutoEventWireup="true" CodeBehind="index.aspx.cs" Inherits="GarageManager.index" %>
<asp:Content ID="Content1" ContentPlaceHolderID="head" runat="server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="server">
    <asp:Panel ID="pnlProducts" runat="server">
    </asp:Panel>
</asp:Content>