Nav.Master.cs

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

namespace TestGrounds
{
    public partial class Nav : System.Web.UI.MasterPage
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            if (Session["user"] != null)
            {
                string user = Session["user"].ToString();
                if (user == null || user == "guest")
                { HideShow("My Account"); }
            }
        }

        protected void HideShow(string link)
        {
            for (int i = 0; i < mnuNav.Items.Count; ++i)
            {
                if (mnuNav.Items[i].Text == link)
                {
                    mnuNav.Items[i].Selectable = false;
                }
            }
        }
    }
}