VIEW STATE IN ASP.NET BY ANIL KUMAR YADAV

                                                     VIEW STATE

      

   VIEW STATE USED HIDDEN FIELDS TO MANAGE THE VALUES

·       WE CAN RETRIEVE THE VALUE AT THE SAME PAGE, WE CAN NOT RETREIVE THE VALUE AT THE NEXT PAGE, WE CAN STORE ONLY STRING VALUE IN HIDDEN FIELD   

·       HERE VALUES ARE MAINTAINED FOR THE SAME PAGE

·       HIDDEN FIELD IS AN CONTROL IN TOOLBOX WHICH IN INVISIBLE AT RUN TIME.

·       THIS IS ALSO NOT A SECURE TECHNIQUE TO MANAGE THE STATE

using System;

using System.Configuration;

using System.Xml.Linq;

public partial class _Default : System.Web.UI.Page

{

    protected void Page_Load(object sender, EventArgs e)

    {

    }

    int i;

    protected void Button1_Click(object sender, EventArgs e)

    {

        if (HiddenField1.Value != "")

        {

            i = int.Parse(HiddenField1.Value);

        }

        i++;

        HiddenField1.Value=i.ToString();

        if(i==3)

        {

            Response.Redirect("Default2.aspx");

        }

    }

}

·       ASP.NET ALWAYS USED VIEW STATE INTERNALLY TO MANAGE THE VALUE OF CONTROLS( STATE OF CONTROLS)

·       VIEW STATE IS AN OBJECT WHICH KEEP DICTIONARY ARCHITECTURE

·       VIEW STATE IS CONVERTED OF STREAM OF BITS AND STORED IT IN HIDDEN FIELD THIS IS CALLED SERIALIZATION

·        

·       SAVE STATE COMPLETE

                         SAVE THE CHANGES HAPPENED BY THE CLIENT ON THE CONTROLS LIKE LABEL

·       IF A PROGRAMMER DONOT WANT TO MAINTAINED THE VIEW STATE OF ANY CONTROLS

   RIGHT CLICK ON CONTROL      PROPERTIES      ENABLE VIEW STATE= FALSE

    

ENABLE VIEW STATE    IS AN PROPERTY TO SET THE PROPERTY OF ANY CONTROL THAT IT STORED IN VIEW STATE OR NOT

int i = 0;

    protected void Button1_Click(object sender, EventArgs e)

    {  

       

       

        if (Label1.Text == "")

        {

            Label1.Text = i.ToString();

        }

        else

        {

            i = int.Parse(Label1.Text);

            i++;

            Label1.Text = i.ToString();

       

        }

    }

 BASE STRING 64 IS AN FORMAT TO ENCODE THE DATA OF CONTROLS AND WE  CAN ALSO RECONVERT IT INTO STRING, SO IT IS NOT A SECURE TECHNIQUE.

·         IF A PROGRAMMER DO NOT WANT TO MANAGE THE VIEW STATE OF THE FULL PAGE WRITE THIS IN SOURCE CODE THIS

      <% PAGE ENABLEVIEWSTATE=” FALSE” LANGUAGE=” C# AUTOEVENWIREUP=”TRUE” CODE FILE=”DEFAULT.ASPX.CS” INHERITS=”DEFAULT” %>

·         IF A PROGRAMMER DON’T WANT TO  MANAGE THE VIEW STATE FOR THE FULL APPLICATION SO DO THIS

    OPEN WEBCONFIG      WRITE

 < SYSTEM.WEB>

<PAGES.ENBALEVIEWSTATE=”FALSE”> </PAGES>

·         IF A PROGRAMMER DO NOT WANT TO MANAGE THE VIEW STATE FOR THE PAGES MORE THAN ONE WHICH ARE STORED IN A FOLDER, SO DO THIS

    RIGHT CLICK ON FOLDER                  ADD NEW ITEM                  ADD WEB CONFIGURATION FILE

             

 WRITE THIS

  <PAGE ENABLEVIEW STATE=”FALSE”></PAGE>

·         WEB APPLICATION NEVER CREATE .EXE IT ALWAYS CREATE DLL,

·       THEIR ARE FEW CONTROLS OF THEIR SINGLE VALUE IS MAINTAIND IN POST DATA WHEN WE HAVE DONE THE VIEW STATE OFF IS NOT DEPENDENT THIS POST DATA IS APPLIED AFTER LOAD STATE

·         FOR THOSE CONTROLS TO WHOM I.POST HANDLER INTERFACE IS IMPLEMENTED SO THE VALUE OF THESE CONTROLS ARE MAINTAIND IN POST DATA LIKE TEXTBOX.TEXT

·           ONLY TEXT IS MAINTAIN NOT COLOR OF THAT TEXTBOX

  @   VIEW STATE IS APPLIED ON CONTROLS IN WHICH STATE OF THE LIFE CYCLE OF A PAGE

  ANS.     AFTER THE INIT COMPLETE AND BEFORE PRELOAD STATE

·       WE CAN STORE THE OBJECT TYPE OF DATA IN VIEW STATE

·       VIEW STATE ALWAYS STORE THE SERIALIZED DATA

                                      PRACTICAL OF VIEWSTATE

using System;

using System.Configuration;

using System.Data;

using System.Linq;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.HtmlControls;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Xml.Linq;

using System.Collections.Generic;

public partial class _Default : System.Web.UI.Page

{

    protected void Page_Load(object sender, EventArgs e)

    {

    }

    List<student> li;

    protected void Button1_Click(object sender, EventArgs e)

    {

        if (ViewState["data"] == null)

        {

            li = new List<student>();

        }

        if (ViewState["data"] != null)

        {

            li = (List<student>)ViewState["data"];

        }

        student obj = new student();

        obj.Sid = Convert.ToInt32(TextBox1.Text);

        obj.Sname = TextBox2.Text;

        obj.Sal = Convert.ToInt32(TextBox3.Text);

        li.Add(obj);

        Response.Write(li.Count);

        ViewState["data"] = li;

    }

    int x;

    protected void Button2_Click(object sender, EventArgs e)

    {

        if (ViewState["count"] != null)

        {

            x = (int)ViewState["count"];

        }

        List<student> li = (List<student>)ViewState["data"];

        student s = li[x];

        TextBox1.Text = s.Sid.ToString();

        TextBox2.Text = s.Sname.ToString();

        TextBox3.Text = s.Sal.ToString();

   

        ViewState["count"] = x;

    }

    protected void Button3_Click(object sender, EventArgs e)

    {

        if (ViewState["count"] != null)

        {

            x = (int)ViewState["count"];

        }

        List<student> li = (List<student>)ViewState["data"];

        x++;

        student s = li[x];

        TextBox1.Text = s.Sid.ToString();

        TextBox2.Text = s.Sname.ToString();

        TextBox3.Text = s.Sal.ToString();

      

        ViewState["count"] = x;

    }

    protected void Button4_Click(object sender, EventArgs e)

    {

        if (ViewState["count"] != null)

        {

            x = (int)ViewState["count"];

        }

        List<student> li = (List<student>)ViewState["data"];

        student s = li[x];

        TextBox1.Text = s.Sid.ToString();

        TextBox2.Text = s.Sname.ToString();

        TextBox3.Text = s.Sal.ToString();

        x--;

        ViewState["count"] = x;

    }

    protected void Button5_Click(object sender, EventArgs e)

    {

    

        if (ViewState["count"] != null)

        {

            x = (int)ViewState["count"];

        }

       

        List<student> li = (List<student>)ViewState["data"];

        x = li.Count - 1;

        student s = li[x];

       

        TextBox1.Text = s.Sid.ToString();

        TextBox2.Text = s.Sname.ToString();

        TextBox3.Text = s.Sal.ToString();

        ViewState["count"]=null;

    }

    protected void Button6_Click(object sender, EventArgs e)

    {

    }

}