What is Caching in ASP.Net and How to implement DataSource Caching ~ Microsoft .Net Expert Call@+91-9555484663

Caching in ASP.Net

Caching is a technique by which we can improve the performance of our web-based application.

Advantage of Caching

• Improve performance

• Avoid time-consumption

• Decrease hosting server round-trips

• Decrease database server round-trips

• Decrease network traffic

Disadvantage of Caching

Where data is different for each click that case caching is not supported Like inbox of GMAIL but you can store data of Sensex
You can not store senstive data in Chache

Types of Caching

DataSource Caching
Pageoutput Caching
Partial Page Caching
Data Caching

Where cache is stored..........................

Server
Client
Proxy Server

DataSource Caching: In this concept all data will be hold in data cache. Advantage of DataSource caching is that the Data Source controls automatically reload when the data is updated.

There are three type of cache in DataSource Caching

1. SqlDataSource

2. ObjectDataSource

3. XmlDataSource

LinqDataSource doesn’t support cache

-- sql query................................

create database test

use test

create table Student

(

RollNo int primary key,

Name varchar(50),

Course varchar(50)

)

1. SqlDataSource Caching

Properties as SqlDataSource

· EnableCaching,

· CacheDuration

· CacheExpirationPolicy

· DataSourceMode

Module1: In this model updated table data show after chache duration.

Code for Default.aspx page.......................

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>

<!DOCTYPE html>

</head>

<body>

<div>

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataKeyNames="RollNo" DataSourceID="SqlDataSource1">

<asp:BoundField DataField="RollNo" HeaderText="RollNo" ReadOnly="True" SortExpression="RollNo" />

<asp:BoundField DataField="Name" HeaderText="Name" SortExpression="Name" />

<asp:BoundField DataField="Course" HeaderText="Course" SortExpression="Course" />

</Columns>

</asp:GridView>

<asp:SqlDataSource ID="SqlDataSource1" runat="server"

ConnectionString="<%$ ConnectionStrings:testConnectionString %>"

SelectCommand="SELECT * FROM [Student] ORDER BY [RollNo]"

CacheDuration="60" EnableCaching="True" CacheExpirationPolicy="Absolute">

</asp:SqlDataSource>

</div>

</form>

</body>

</html>

ByDefault cache is working with disConnected mode Dataset when you will select datareader you will find this type error. The data source 'SqlDataSource1' only supports caching when the data source's DataSourceMode is set to DataSet.

Note : There are two type of CacheExpirationPolicy in SqlDataSource Caching one is Absolute and another is Sliding different b/w both ,Absolute is using for store data in cache memory for a particular interval of time but It’s very important in case of data that does not changed often like your data change in once in every minute. When you are working with large data, then you should be used to sliding cache policy. Advantage of this policy is that data remains in cache as long as continues to be requested within particular interval of time.

Module2: When table data is updated automatically SqlDataSource control reload cache data from table.

Advantage of creating key dependency is that when sql table updated then, SqlDataSource automatically reload cache data without any cache duration.

First we will add Global.asax in our web-application put the below code in

<%@ Application Language="C#" %>

void Application_Start(object sender, EventArgs e)

{

// Code that runs on application startup

HttpContext context = HttpContext.Current;

context.Cache.Insert ("CacheKey", DateTime.Now, null, DateTime.MaxValue,Cache.NoSlidingExpiration, CacheItemPriority.NotRemovable, null);

}

...........................

Code for Default.aspx page.......................

<div>

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataKeyNames="RollNo" DataSourceID="SqlDataSource1">

<asp:BoundField DataField="RollNo" HeaderText="RollNo" ReadOnly="True" SortExpression="RollNo" />

<asp:BoundField DataField="Name" HeaderText="Name" SortExpression="Name" />

<asp:BoundField DataField="Course" HeaderText="Course" SortExpression="Course" />

</Columns>

</asp:GridView>

<asp:SqlDataSource ID="SqlDataSource1" runat="server"

ConnectionString="<%$ ConnectionStrings: testConnectionString %>"

SelectCommand="SELECT * FROM [Student] ORDER BY [RollNo]"

EnableCaching="true"

CacheDuration="200"

CacheExpirationPolicy="Absolute"

CacheKeyDependency="CacheKey"

</asp:SqlDataSource>

</div>

</form>

We are creating another webpage which name is AddNewStudent.aspx

Code for AddNewStudent.aspx page.......................

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="AddNewStudent.aspx.cs" Inherits="AddNewStudent" %>

<!DOCTYPE html>

.auto-style1 {

width: 100%;

}

.auto-style2 {

height: 23px;

}

</style>

</head>

<body>

<div>

<tr>

</tr>

<tr>

<td class="auto-style2">RollNo</td>

<asp:TextBox ID="txtRollNo" runat="server"></asp:TextBox>

</td>

</tr>

<tr>

<td>

<asp:TextBox ID="txtName" runat="server"></asp:TextBox>

</td>

</tr>

<tr>

<td>Course</td>

<td>

<asp:TextBox ID="txtCourse" runat="server"></asp:TextBox>

</td>

</tr>

<tr>

<td>

<asp:Button ID="btnSave" runat="server" OnClick="btnSave_Click" Text="Save" />

</td>

</tr>

</table>

</div>

</form>

</body>

</html>

Code for AddNewStudent.aspx.cs page.......................

using System;

using System.Data.SqlClient;

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

{

protected void Page_Load(object sender, EventArgs e)

{

}

protected void btnSave_Click(object sender, EventArgs e)

{

SqlConnection con = new SqlConnection(@"Data Source=USER;Initial Catalog=test;User ID=sa;Password=tiwari");

SqlCommand cmd = new SqlCommand("insert into Student values("+Convert.ToInt32(txtRollNo.Text)+",'"+txtName.Text+"','"+txtCourse.Text+"')",con);

con.Open();

cmd.ExecuteNonQuery();

con.Close();

// Cache.Insert("Cachekey", DateTime.Now);

Response.Write("Saved");

}

2. ObjectDataSource Caching

EnableCaching,

· CacheDuration

· CacheExpirationPolicy

· DataSourceMode

· TypeName

· SelectMethod

We will take a seperate class for ObjectDataSource Caching which name is Student class

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

// using this name sapce

using System.Configuration;

using System.Data;

using System.Data.SqlClient;

public class Student

{

public static DataTable StudentData()

{

SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["testConnectionString"].ToString());

DataTable dt = new DataTable();

con.Open();

SqlDataAdapter da = new SqlDataAdapter("Select * from Student", con);

da.Fill(dt);

con.Close();

return dt;

}

Code for Default2.aspx page.......................

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default2.aspx.cs" Inherits="Default2" %>

<!DOCTYPE html>

</head>

<body>

<div>

<asp:GridView ID="GridView1" runat="server" DataSourceID="ObjectDataSource1">

</asp:GridView>

<asp:ObjectDataSource ID="ObjectDataSource1" runat="server"

TypeName="Student"

SelectMethod="StudentData"

EnableCaching="true"

CacheExpirationPolicy="Absolute"

CacheDuration="15">

</asp:ObjectDataSource>

</div>

</form>

</body>

</html>

3.XmlDataSource Caching

XmlDataSource contains same properties as SqlDataSource and ObjectDataSource but XmlDataSource cache by default and it’s automatically creates file dependency on attached xml file, means when xml file is modified, its automatically reloads data.

Step 1: we will take anoher Folder which name is Data in our WebApplication and create a xml which name is StuXml.xml

Code for StuXml.xml file...................

<?xml version="1.0" encoding="utf-8" ?>

</Students>

Code for Default3.aspx page.......................

</head>

<body>

<div>

<asp:GridView ID="GridView1" runat="server" DataSourceID="XmlDataSource1" >

</asp:GridView>

<asp:XmlDataSource ID="XmlDataSource1" runat="server"

DataFile="~/Data/StuXml.xml">

</asp:XmlDataSource>

</div>

</form>

</body>

</html>

Result

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Thursday 11 June 2015