SESSION

Whenever client sends request to server for the first time server will process the client request ,allot some memory .To this client known as Session and a unique Id is given known as SessionId.Then Every time response from the server ,request form the client will be transferred using this Id.

S1:-client sends the request to the server for the first time.

S2:-server will process the client request, allot memory to the client known as Session. unique id is given i.e.,SessionId

S3:-Response is delivered to the client along with SessionId.

S4:-client will send the next request along with Session Id.

• As long as client working with the server the request & response will be transferred using the same session Id.
• When session is destroyed at Server Session Id will also Destroyed.
• A Session is destroyed in two situations
• When session timeout period completes
• When we kill the session programmatically using Session.Abandon().
• Default timeout period of a session is “20” minutes.
• In general a session is local to particular client.
• The session data of any session is accessible to particular client by whom it is created in general any client cannot access other clients session data.
• A session Id is “120 bits/15 bytes” key maximum sessions are created at server are 2¹²⁰
• Within this session we can create variables called session variable

 To create Session Variables we use the Syntax like:-

              Sy:-   Session[“Variable Name”]=Data;

              Ex:-   Session[“a”]=20;

                        Session[“b”]=20.5

                        Session[“UName”]=”sampath"

To access Session variables we use Index value or variable name like:-

   

Session[0]

   OR

Session[“a”]

Session[1]

     OR

Session[“b”]

Session[2]

     OR

Session[“UName”]

• Session variables will store the data & Return the data with object type .
• Session can store any amount of data in general there is no restriction for the memory of the session
• For each browser request sent from a single machine a separate session will be created at Server side.

Methods with Session Object:-

[1] Abandon()  : - used to kill the Session programmatically

Properties with Session :- 

[1] SessionId : -This is Readonly property which returns the session Id of current Session“Session Id is 120 bit code” automatically generated by server.                

Example to work WithSession:-

Create Two WebPages SourceS.aspx,TargetS.aspx

Design SourceS.aspx by taking a Textbox & a Button like

 

Set the following Properties for theTextBox1

    

ID                    ---        txtEmpId

Set the following Properties for the Button1
 

 ID                    ---        btnSubmit

Name               ---        Submit

Goto Source and write the Following Code in btnSubmit Click Event:-

protected void btnSubmit_Click(object sender, EventArgs e)     {         Session["EmpId"] = txtEmpId.Text;         Response.Redirect("TargetSs.aspx");     }

             

Design TargetS.aspx by taking a GridView like

 

Goto Source and write the following code in Page Load Event of TargetS.aspx

           

public partial class TargetSs : System.Web.UI.Page { SqlConnection Con = new SqlConnection("Server=.;User Id=sa;password=Admin123;DataBase=Employee");           SqlDataAdapter Da;          protected void Page_Load(object sender, EventArgs e)           { string q = "Select * from EmpDetails where EmpId=" + Session["EmpId"].ToString();             Da = new SqlDataAdapter(q, Con);             DataSet Ds = new DataSet();            Da.Fill(Ds);            GridView1.DataSource = Ds.Tables[0];            GridView1.DataBind();           } }