Can't find ASP.NET master page

I'm trying to get my content page to be able to access an ASP:Literal on a master page.

I have my content page as:

<%@ Page Language=开发者_运维百科"C#" AutoEventWireup="true" CodeBehind="viewProduct.aspx.cs" Inherits="AlphaPackSite.viewProduct" Title="Hi there!" %>
<%@ MasterType TypeName="Main" %>

Then my master page called Main.master has:

<asp:Literal runat="server" ID="lblBasket" />

But from the content page when I try and do:

Master.basket.Text = "test";

I get:

Error 46 The type or namespace name 'Main' could not be found (are you missing a using directive or an assembly reference?)

The error is on the designer page:

public new Main Master {
    get {
        return ((Main)(base.Master));
    }
}

My master page code behind is:

namespace AlphaPack.MasterPages
{
    public partial class Main : System.Web.UI.MasterPage
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            this.IsLoggedIn = Request.IsAuthenticated;
        }

        public bool IsLoggedIn
        {
            get { return this.ViewState["isLoggedIn"] as bool? ?? false; }
            set { this.ViewState["isLoggedIn"] = value; }
        }
    }
}

Is the designer within your AlphaPack.MasterPages namespace?

The MasterType isn't fully qualified, should it be? Don't you have to provide a path as well? (Not familiar with, sorry).

How does this respond if you use a MasterPageFile reference instead of a MasterType?

<%@ Page Language="C#" MasterPageFile="~MasterPages/Main.Master" AutoEventWireup="true" CodeBehind="viewProduct.aspx.cs" Inherits="AlphaPackSite.viewProduct" Title="Hi there!" %>

<%@ Page MasterPageFile="~/MasterPages/Main.master" .. %>
<%@ MasterType VirtualPath="~/MasterPages/Main.master" .. %>

Okey, that's how it looks in my own app:

Master page (Site.master, in the root):

<%@ Master Language="C#" AutoEventWireup="True" CodeBehind="Site.master.cs" Inherits="Project.SiteMaster" %>

It's code-behind:

namespace Project
{
    public partial class SiteMaster : System.Web.UI.MasterPage { } 
}

Content page (Test.aspx, in the root):

<%@ Page Language="C#" AutoEventWireup="True" CodeBehind="Test.aspx.cs" Inherits="Project.Test" MasterPageFile="~/Site.master" Title="Test" %>

it's code-behind:

namespace Project
{
    public partial class Test : System.Web.UI.Page { }
}

That's how auto-generated code looks like:

namespace Project {
    public partial class SiteMaster {            
        /// <summary>
        /// lblBasket control.
        /// </summary>
        /// <remarks>
        /// Auto-generated field.
        /// To modify move field declaration from designer file to code-behind file.
        /// </remarks>
        protected global::System.Web.UI.WebControls.Literal lblBasket;
    }
}

So create a property but don't share the control itself, only text:

public string BasketText
{
    get { return this.lblBasket.Text; } 
    set { this.lblBasket.Text = value; }
}