ASP.NET is a
web development platform, which provides a programming model, a comprehensive
software infrastructure and various services required to build up robust web
applications for PC, as well as mobile devices.
ASP.NET works
on top of the HTTP protocol, and uses the HTTP commands and policies to set a
browser-to-server bilateral communication and cooperation.
ASP.NET is a
part of Microsoft .Net platform. ASP.NET applications are compiled codes,
written using the extensible and reusable components or objects present in .Net
framework. These codes can use the entire hierarchy of classes in .Net
framework.
The ASP.NET application codes can be
written in any of the following languages:
C#
Visual
Basic.Net
Jscript
J#
ASP.NET is
used to produce interactive, data-driven web applications over the internet. It
consists of a large number of controls such as text boxes, buttons, and labels
for assembling, configuring, and manipulating code to create HTML pages.
ASP.NET Web Forms Model
ASP.NET web
forms extend the event-driven model of interaction to the web applications. The
browser submits a web form to the web server and the server returns a full
markup page or HTML page in response.
All client
side user activities are forwarded to the server for stateful processing. The
server processes the output of the client actions and triggers the reactions.
Now, HTTP is
a stateless protocol. ASP.NET framework helps in storing the information
regarding the state of the application, which consists of:
Page state
Session state
The page
state is the state of the client, i.e., the content of various input fields in
the web form. The session state is the collective information obtained from
various pages the user visited and worked with, i.e., the overall session
state. To clear the concept, let us take an example of a shopping cart.
User adds
items to a shopping cart. Items are selected from a page, say the items page,
and the total collected items and price are shown on a different page, say the
cart page. Only HTTP cannot keep track of all the information coming from
various pages. ASP.NET session state and server side infrastructure keeps track
of the information collected globally over a session.
The ASP.NET
runtime carries the page state to and from the server across page requests
while generating ASP.NET runtime codes, and incorporates the state of the
server side components in hidden fields.
This way, the
server becomes aware of the overall application state and operates in a
two-tiered connected way.
The ASP.NET Component Model
The ASP.NET
component model provides various building blocks of ASP.NET pages. Basically it
is an object model, which describes:
Server side
counterparts of almost all HTML elements or tags, such as <form> and
<input>.
Server
controls, which help in developing complex user-interface. For example, the
Calendar control or the Gridview control.
ASP.NET is a
technology, which works on the .Net framework that contains all web-related
functionalities. The .Net framework is made of an object-oriented hierarchy. An
ASP.NET web application is made of pages. When a user requests an ASP.NET page,
the IIS delegates the processing of the page to the ASP.NET runtime system.
The ASP.NET
runtime transforms the .aspx page into an instance of a class, which inherits
from the base class page of the .Net framework. Therefore, each ASP.NET page is
an object and all its components i.e., the server-side controls are also
objects.
Components of .Net Framework 3.5
Before going
to the next session on Visual Studio.Net, let us go through at the various
components of the .Net framework 3.5. The following table describes the
components of the .Net framework 3.5 and the job they perform:
Components and their Description
(1) Common
Language Runtime or CLR
It performs
memory management, exception handling, debugging, security checking, thread
execution, code execution, code safety, verification, and compilation. The code
that is directly managed by the CLR is called the managed code. When the
managed code is compiled, the compiler converts the source code into a CPU
independent intermediate language (IL) code. A Just In Time(JIT) compiler
compiles the IL code into native code, which is CPU specific.
(2) .Net
Framework Class Library
It contains a
huge library of reusable types. classes, interfaces, structures, and enumerated
values, which are collectively called types.
(3) Common
Language Specification
It contains
the specifications for the .Net supported languages and implementation of
language integration.
(4) Common
Type System
It provides
guidelines for declaring, using, and managing types at runtime, and
cross-language communication.
(5) Metadata
and Assemblies
Metadata is
the binary information describing the program, which is either stored in a
portable executable file (PE) or in the memory.
Assembly is a logical unit
consisting of the assembly manifest, type metadata, IL code, and a set of
resources like image files.
(6) Windows
Forms
Windows Forms
contain the graphical representation of any window displayed in the application.
(7) ASP.NET
and ASP.NET AJAX
ASP.NET is
the web development model and AJAX is an extension of ASP.NET for developing
and implementing AJAX functionality. ASP.NET AJAX contains the components that
allow the developer to update data on a website without a complete reload of
the page.
(8) ADO.NET
It is the
technology used for working with data and databases. It provides access to data
sources like SQL server, OLE DB, XML etc. The ADO.NET allows connection to data
sources for retrieving, manipulating, and updating data.
(9) Windows
Workflow Foundation (WF)
It helps in
building workflow-based applications in Windows. It contains activities,
workflow runtime, workflow designer, and a rules engine.
(10) Windows
Presentation Foundation
It provides a
separation between the user interface and the business logic. It helps in
developing visually stunning interfaces using documents, media, two and three
dimensional graphics, animations, and more.
(11) Windows
Communication Foundation (WCF)
It is the
technology used for building and executing connected systems.
(12) Windows
CardSpace
It provides
safety for accessing resources and sharing personal information on the
internet.
(13) LINQ
It imparts
data querying capabilities to .Net languages using a syntax which is similar to
the tradition query language SQL.