ASP.Net C# 引用 Site.master 上的元素返回：对象引用未设置为对象的实例

Question

I've found threads solving this issue within Default.aspx and Default.aspx.cs, but applying those solutions to my problem don't fix my issue. None of them are helpful in this context:

I'm trying to access an element on my Site.master page within Default.aspx.cs. I want to hide this element if a certain condition isn't met. However, I cannot reference any elements within my Site.master page (either within Default.aspx.cs OR Site.master.cs)

Code:

Site.master:

<li><a runat="server" id="editLink" href="~/Edit">Edit</a></li>

Default.aspx.cs:

MasterPage master = this.Master;
Control linkControl = master.FindControl("editLink");
linkControl.Visible = false;

I've also tried:

Site.master:

<asp:Panel ID="Panel1" runat="server">
    <li><a runat="server" id="editLink" href="~/Edit">Edit</a></li>
</asp:Panel>

Default.aspx.cs:

((Panel)Master.FindControl("Panel1")).Visible = false;
//or..
//Panel testPanel = ((Panel)Master.FindControl("Panel1"));
//Panel1.Visible = false;

I don't know where to start. Thanks!

EDIT:

I've tried to apply resolutions from:

ASP.NET - Accessing Master Page elements form the Content Page

What is a NullReferenceException, and how do I fix it?

Specifically from the first:

adding the following to Default.aspx

<%@ MasterType virtualpath="~/Site.master" %>

adding the following to Default.aspx.cs

Panel testPanel = (Panel)Master.FindControl("Panel1");       
testPanel.Visible = true;

The above code is the suggested fix for the first thread, but I get the same error. The second thread seemed to suggest I was referencing the element before it was created thus returning the nullreferenceexception error, but I do not believe this is the case. Ultimately, I do not understand enough to utilize those threads.

EDIT

Site.master MCVE:

<%@ Master Language="C#" AutoEventWireup="true" CodeFile="Site.master.cs" Inherits="SiteMaster" %>

<form id="wrapForm" runat="server">
    <asp:ScriptManager runat="server" EnablePageMethods="true"></asp:ScriptManager>
    <asp:ContentPlaceHolder ID="MainContent" runat="server">
      <asp:Panel ID="Panel1" runat="server">Test Text</asp:Panel>
    </asp:ContentPlaceHolder>
</form>

Default.aspx.cs MCVE:

protected void Page_Load(object sender, EventArgs e)
{
    Panel testPanel = (Panel)Master.FindControl("Panel1"); 
    testPanel.Visible = true;
}

Answer 1

MasterType <= 根据ASP.NET应该是Reference - 访问母版页元素形成内容页？

<%@ Reference virtualpath="~/Site.master" %>