如何从App_Code引用ASP.net MasterPage

public partial class MyMasterPage : System.Web.UI.MasterPage
{
    public string MyProperty { get; set; }

    public void MyMethod()
    {
        // Your code here
    }
}

<%@ Page Language="C#" MasterPageFile="~/MyMasterPage.master" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" Title="Untitled Page" %>

<%@ MasterType VirtualPath="~/MyMasterPage.master" %>

protected void Page_Load(object sender, EventArgs e)
{
    this.Master.MyProperty = "Hello, World!";
    this.Master.MyMethod();
}

<%@ Page Language="C#" MasterPageFile="~/MyMasterPage.master" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" Title="Untitled Page" %>