Chapter 5 - Introduction to ASP.NET

8/9/2019 Chapter 5 - Introduction to ASP.NET

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ASP.NET Introduction

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Objective

At the end of this chapter, you will be able to

understand what ASP.NET is and how the ASP &

ASP.NET pages work.

Besides, youll be able to understand the advantagesASP.NET provides over ASP.


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Scope

Introduction to ASP

Introduction to ASP.NET

How ASP.NET works

Advantage of ASP.NET over ASP

Pre requisite for learning ASP.NET

Language support

What is HTTP

Writing first ASP.NET Page


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Microsoft introduced Active Server Pages in

December 1996. Microsoft made it available for its

Internet Information Server (IIS).

ASP Page is saved with an extension of .asp e.g.test.asp, which is interpreted at the server end.

ASP code can be written in VBScript or Jscript or

Perl or any other scripting language provided theserver has a scripting engine available for script.

Introduction to ASP


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How ASP work

The working of an ASP page can be well understood

with following 8 steps.

A user enters the web site name in the URL using

his browser.

Internet then connects to the specified server where the

Web page resides.

The requested server is a Windows NT server running the

IIS.


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How ASP work

The Web server receives the request, and searches

for the specified file, which may be an ASP file or a

HTML file, which contains a HTML form.

The server then sends this file to the browser, or tothe client, where the user is supposed to fill in the

form and submit it to the server.


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How ASP work

User then fills up the form and clicks the SUBMIT

button on the form, the information in the form is

sent to the server along with the name of an ASP

program whose name was embedded into thisHTML file.

The server gets the requested ASP file along with

the information in the form and interprets it using

the ASP.dll


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How ASP work

If during the processing of ASP it needs some

information from a database, it connects to the

database and retrieves the required information from

it using some COM components like the ActiveXdata objects (ADO)

The ASP file is processed and the results are

generated in standard HTML

This file containing the standard HTML is sent back

to user where the browser displays the result.


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ASP Objects

An Object can be defined as something that has

methods, properties, and collections.

ASP has the following built-in objects :

The ScriptingContextObject: It is available

to the scripting host along with the scripting objects.

The RequestObject

The Response Object

The Application Object

The Session Object

The Server Object


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Introduction to ASP.NET

ASP.NET has been built on common language

runtime that can be used on a server to build

powerful web Applications.

It is a part of emerging Microsoft .NET platform andprovides innovative ways to build and deploy the

next generation of ASP for use in high performance

web solutions.

ASP.NET is largely syntax compatible with ASP.


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How ASP.NET Works

The working of an ASP page can be well understood

with following steps. Whole process can be divided

into 8 steps, which are as follows.

A user requests for an ASP.NET page in hisbrowser.

An HTTP request is sent to IIS.

The xspisapi.dll filters the request and passes therequest to XSP worker process (XSPWP.EXE).


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How ASP.NET Works

The requested .aspx page (ASP.NET page is saved

with an extension of .aspx) is read from hard disk or

cache memory and a new class is generated which

contains the programming logic of the aspx page.This class is loaded in the memory and executed.

The server side code generates normal HTML page,

which is sent back to IIS following the same route.

IIS sends the page to browser.


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How ASP.NET Works

Now if the user clicks in the page or after filling

some information again sends the page back to the

server.

The new class handles all the queries sent by theuser. Requests are processed by this class and

response is prepared.

Another HTML page is generated after processingthe information sent by the user. This HTML page is

sent to the user.


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Better Performance

The ASP.NET page is not read like a new page every

time.

An ASP.NET file is compiled only the first time it isaccessed.

If the page has been sent back then, only modified area is

read at server. Next request for the same page will use the

compiled type instance.

ASP.NET over ASP


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Simplicity

ASP.NET framework allows you to create a web

application that cleanly separates application logic from

presentation code. Also common language runtime simplifies development

with managed code services like garbage collection,

debugging facility and automatic reference counting.

ASP.NET over ASP


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Better tool support

At the core of ASP.NET is its HTTP runtime (different

from common language runtime), a high performance

execution engine for processing HTTP commands. The HTTP runtime is responsible for processing all the

incoming HTTP requests.

ASP.NET is support for live updating of applications.

ASP.NET over ASP


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Language support

ASP.NET supports all the languages supported by the

.NET Framework.

ASP.NET currently offers support for three languages:C#, VB.NET and Jscript.NET.

ASP.NET over ASP


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Security

ASP.NET supports HTML forms based authentication.

ASP.NET works in conjunction with IIS to provide

authentication and authorization services to applications. As soon as the authentication is done process of

authorization may start.

ASP.NET over ASP

AS d


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Separation of code from html code

You can separate your programming code from normal

HTML part.

This makes easier to create, maintain and modify anyASP.NET page.

ASP.NET over ASP

ASP NET I d i


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Less code

ASP.NET has been enriched with server controls.

This reduces amount of coding that you need to write.

All you have to do is to use below mentioned directive: -

ASP.NET over ASP

ASP NET I d i


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Caching

Caching is a technique that is used widely to increase the

performance by keeping frequently accessed or expensive

data in memory. ASP.NET offers three types of caching

Output caching

Data caching

Fragment caching

ASP.NET over ASP

ASP NET I d i


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ASP.NET has been simplified a lot which makes it

very easy to learn.

All you need is knowledge of HTML, internet and a

language supported in .NET framework.

You have the option to choose any of three

languages, presently supported in ASP.NET.

VB.NET C#

Jscript

Pre-Requisite for ASP.NET

ASP NET I t d ti


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Language Support

Now let us see how ASP.NET supports these three

languages.

All you have to do is declare which language you

will be using in your ASP.NET page, in thefollowing syntax at the start of your page.

VB is the default language for ASP.NET

ASP NET I t d ti


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What is HTTP?

HTTP (Hyper Text Transfer Protocol) is used for

transferring the messages between web server and

web browser.

HTTP protocol specifies how messages can betransported over the TCP/IP network between web

server and web browser.

It specifies the ways in which a browser and Webserver can interact.

ASP NET I t d ti


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What is HTTP?

Whenever you retrieve a page from a web site, yourbrowser opens a connection to a web server for thatsite and sends a request.

The web server receives the request and issues aresponse.

All communication between a browser and a webserver takes place with the help of request and

response pair. HTTP protocol is also known as request and

response protocol.

ASP NET I t d ti


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A browser request has a certain standard structure.

A request might also contain a message body or

entity body.

Every response begins with the status line, contains

several headers, and may contain a message body.

A status line indicates the protocol being used, a

status code, and a text message.

What is HTTP?

ASP NET Introduction


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Configuring IIS 5.0

To write your first ASP.NET page, first of all create a

directory.

Now click on StartProgramsAdministrative ToolsInternet Services Manager

Now right click on Default Web Site on the left window

and select New and Virtual Directory

Writing First ASP.NET Page



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Once you click on the Virtual Directory you will

view the following screen :

Configuring IIS 5.0



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Click on next and type the Alias name i.e. this is the

name of your default directory.

Next screen will ask for the existing directory, which

will contain all the real examples.

Here you will be giving the name of the directory,

which was created initially.

Again click on next and the next screen will tell youthat you have successfully completed the virtual

directory creation wizard. Click on finish.

Configuring IIS 5.0



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Creating ASP.NET Application

Open Microsoft Visual Studio .NET.

In the start page click on New Project button.

Click on ASP.NET Web Application

Give a name say Ch1 and specify the location of

the virtual directory that you created using IIS.

In the Toolbox, under the Web Forms tab, drag a

button and drop it on the form.



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Set the ID property of the button to clickBtn

Set the Text property of the button to Click Me.

Now double click on the button to open the code

window which shows the click event of the button.

Write the following code in it :

clickBtn.Text= Hello ASP.NET



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Click on the Start button and your application runs

in the browser and on click of the button, you can

see the text on the button changing.

Or

View the output of your aspx page by opening

internet explorer and type in the URL

http://localhost/WebForms/Ch1/WebForm1.asp



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You will see the

followingoutput.




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Configuring Front Page 2002

The following steps need to be performed in Front

Page to create a new web site.

Open Front Page 2002 and click on Menu item File

New Page or Web. Select the option empty web from the right window.



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A dialog box is displayed, select one page web from

it and in the location textbox specify a folder in C

drive say, FrontPageWeb.



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Your web is now created using Front Page.

Double click on the index page (this is the home

page of your web site).

Click on new page button on the toolbar to add a

new page.

Save this page with an .aspx extension say,

one.aspx.



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Go to HTML tab and write the following code



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Add a hyperlink in home page which points to the

new .aspx page by clicking on Menu Item Insert

Hyperlink.



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Now Click on the publish button in the toolbar or go

to Menu item FilePublish Web.

Specify the URL of your web site say

http://localhost/aa and click on PUBLISH Button.



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Click on the first hyperlink i.e. Click here to view

your published site to display your web site on the

Web Browser.



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Click on the hyperlink on the web page to display

your .aspx page on the web browser.



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The Output would be as follows :



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Key points covered in this chapter are:

ASP lacks in performance as it supports scripting languages

only. ASP.NET has been introduced by Microsoft under

.NET framework, to overcome the drawbacks of ASP To understand ASP.NET, you should have knowledge of

any language supported in .NET Framework and familiarity

with the environment of Visual Studio.NET.

ASP.NET provides lots of advantages over ASP e.g.performance, tool support, rich hierarchy, separation of

code from HTML code, less code, caching etc.

Summary



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ASP.NET supports three languages at present i.e. VB, C#,

Jscript.

HTTP is a protocol, which defines rules to be followed by

the web browser and server.

ASP.NET page or the Web Forms can be created from a

simple notepad or the Visual Studio.NET IDE and even

from Front Page 2002.

Configuration of IIS 5.0 Server

Configuration of Front Page Server extensions.

Summary



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Self Assessment

State True or False

ASP understands only compile type languages.

ASP.NET has replaced ASP completely.

ASP.NET is interpreted at the server. ASP supports only 3 objects.

ASP.NET supports C# and VB.

ASP.NET supports JavaScript.

ASP.NET supports caching.

ASP.NET requires heavy coding from the developer for

any task.



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Fill in the blanks

Caching is used to save ______________ accessed data at

the server end. (Frequently / rarely).

Self Assessment

Date post:	30-May-2018
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Chapter 5 - Introduction to ASP.NET

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