Global.asax.cs

protected void Session_Start(object sender, EventArgs e)
        {
             this.UpdateViewedPagesSession();
            this.UpdateViewedCategoriesSession();
        }
		
		 protected void UpdateViewedPagesSession()
        {
            HttpCookie myCookie = null;

            try
            {
                myCookie = this.Request.Cookies["EPi: ViewedPages"];
            }
            catch (HttpException)
            {
            }

            if (myCookie == null)
            {
                return;
            }

            HashSet<PageReference> viewedPages = JsonConvert.DeserializeObject<HashSet<PageReference>>(myCookie.Value);
            HttpContext.Current.Session["EPi:ViewedPages"] = viewedPages;
        }
		
		protected void UpdateViewedCategoriesSession()
        {
            try
            {
                foreach (string key in
                    this.Request.Cookies.Keys.Cast<string>().Where(key => key.Contains("EPi:VisitedCategories")))
                {
                    HttpCookie myCookie = null;

                    try
                    {
                        myCookie = this.Request.Cookies[key];
                    }
                    catch (HttpException)
                    {
                    }

                    if (myCookie == null)
                    {
                        return;
                    }

                    if (myCookie.Value.Equals("true", StringComparison.OrdinalIgnoreCase))
                    {
                        HttpContext.Current.Session[key] = JsonConvert.DeserializeObject<bool>("true");
                    }
                    else
                    {
                        HashSet<PageReference> viewedCategories = JsonConvert.DeserializeObject<HashSet<PageReference>>(myCookie.Value);
                        HttpContext.Current.Session[key] = viewedCategories;
                    }
                }
            }
            catch (HttpException)
            {
            }
            catch (ArgumentNullException)
            {
            }
            catch (InvalidCastException)
            { 
            }
            catch (ArgumentException)
            {
            }
    }

PageControllerBase.cs

public virtual void UpdateViewedPagesCookie()
        {
            HttpSessionStateBase httpSessionStateBase = null;

            try
            {
                httpSessionStateBase = this.ControllerContext.HttpContext.Session;
            }
            catch (NotImplementedException)
            {
            }

            if (httpSessionStateBase == null)
            {
                return;
            }

            HashSet<PageReference> viewedPages = null;
            try
            {
                viewedPages = httpSessionStateBase["EPi:ViewedPages"] as HashSet<PageReference>;
            }
            catch (NotImplementedException)
            {
            }

            if (viewedPages == null)
            {
                return;
            }

            string content = JsonConvert.SerializeObject(viewedPages);

            HttpCookie myCookie = this.Request.Cookies["EPi: ViewedPages"];

            if (myCookie == null)
            {
                try
                {
                    myCookie = new HttpCookie("EPi: ViewedPages") { Value = content, Expires = DateTime.Now.AddYears(1) };
                    this.Response.Cookies.Add(myCookie);
                }
                catch (ArgumentOutOfRangeException)
                {
                }
                catch (NotImplementedException)
                {
                }

                return;
            }

            try
            {
                myCookie.Value = content;
                myCookie.Expires = DateTime.Now.AddYears(1);
                this.Response.Cookies.Set(myCookie);
            }
            catch (ArgumentOutOfRangeException)
            {
            }
            catch (NotImplementedException)
            {
            }
        }
		
		
		public void UpdateVisitedCategoriesCookie()
        {
            HttpSessionStateBase httpSessionStateBase = null;

            try
            {
                httpSessionStateBase = this.ControllerContext.HttpContext.Session;
            }
            catch (NotImplementedException)
            {
            }

            if (httpSessionStateBase == null)
            {
                return;
            }

            HashSet<PageReference> viewdcategories = null;
            
            try
            {
                foreach (string key in httpSessionStateBase.Keys.Cast<string>().Where(key => key.Contains("EPi:VisitedCategories")))
                {
                    HttpCookie myCookie = this.Request.Cookies[key];
                    string content = string.Empty;

                    try
                    {
                        viewdcategories = httpSessionStateBase[key] as HashSet<PageReference>;
                    }
                    catch (NotImplementedException)
                    {
                    }

                    content = viewdcategories != null ? JsonConvert.SerializeObject(viewdcategories) : JsonConvert.SerializeObject(true);
                    

                    if (myCookie == null)
                    {
                        try
                        {
                            myCookie = new HttpCookie(key) { Value = content, Expires = DateTime.Now.AddYears(1) };
                            this.Response.Cookies.Add(myCookie);
                        }
                        catch (ArgumentOutOfRangeException)
                        {
                        }
                        catch (NotImplementedException)
                        {
                        }
                    }
                    else
                    {
                        try
                        {
                            myCookie.Value = content;
                            myCookie.Expires = DateTime.Now.AddYears(1);
                            this.Response.Cookies.Set(myCookie);
                        }
                        catch (ArgumentOutOfRangeException)
                        {
                        }
                        catch (NotImplementedException)
                        {
                        }
                    }
                }
            }
            catch (NotImplementedException)
            {
            }
            catch (ArgumentNullException)
            {
            }
            catch (InvalidCastException)
            {
            }
        }