Asp.Net Concepts(Master page,cookies,cache)

Reference ASP.NET Master Page Content
===================================================
(1)Add this tage in .aspx

<%@ MasterType virtualpath="~/Masters/Master1.master" %>

void Page_Load()
{
    // Gets a reference to a TextBox control inside 
    // a ContentPlaceHolder
    ContentPlaceHolder mpContentPlaceHolder;
    TextBox mpTextBox;
    mpContentPlaceHolder = 
      (ContentPlaceHolder)Master.FindControl("ContentPlaceHolder1");
    if(mpContentPlaceHolder != null)
    {
        mpTextBox = 
            (TextBox) mpContentPlaceHolder.FindControl("TextBox1");
        if(mpTextBox != null)
        {
            mpTextBox.Text = "TextBox found!";
        }
    }
    
    // Gets a reference to a Label control that not in 
    // a ContentPlaceHolder
    Label mpLabel = (Label) Master.FindControl("masterPageLabel");
    if(mpLabel != null)
    {
        Label1.Text = "Master page label = " + mpLabel.Text;
    }
}

(2)Adding cookie and read cookie

===================================================================

(a)Add cookie

=============

Response.Cookies.Remove("HomeSpecialtyorDoctorSearch");
HttpCookie cookie = new HttpCookie("HomeSpecialtyorDoctorSearch");
Response.Cookies.Add(cookie);

cookie.Values.Add("CityId", ddlCity.SelectedValue);
cookie.Values.Add("CityName", ddlCity.SelectedItem.Text);

(b)Read cookie

===============

HttpCookie cookie = Request.Cookies.Get("HomeSpecialtyorDoctorSearch");
        if (cookie.Values["CityId"] != null)
        {
                appointmentTypeId = Convert.ToInt32(cookie.Values["CityId"]);
        }

(3)Cache 

===========================================================

(a)Add cache

=============

if (HttpRuntime.Cache["HospitalsDataDDl"] == null)
        {
            hospitalList = _GetTransactionData.GetHospitalInformation();
            if (hospitalList.Count > 0)
            {
                HttpRuntime.Cache["HospitalsDataDDl"] = hospitalList;
            }
        }
        else
        {
            hospitalList = (List<RHospitalBO>)HttpRuntime.Cache["HospitalsDataDDl"];
        }

(b)Remove cache

=================

HttpRuntime.Cache.Remove("HospitalsDataDDl");