Why use .net by naveen kumar veligeti

Naveen Kumar Veligeti

Why Use .NET?
.NET hasn’t traditionally been the SitePoint community’s framework of choice for
Web development. A simple comparison of the activity within the PHP and the .NET
forums highlights this fact. But with the release of SitePoint’s first ASP.NET book, I
thought it was about time us .NETers stood proud, and shouted from the rooftops exactly
what makes this technology so good.
However, it isn’t the purpose of this article to deride other technologies; this isn’t "PHP
vs. .NET Part 2". Every platform, framework, and architecture has its own strengths and
weaknesses, and .NET is no exception. So, the features highlighted in this article aren’t discussed
as if they are unique or necessarily better in .NET (although, of course, most are!), but it should
give those who are still dipping toes into .NET some good reasons to dive right in.
The Framework
Without writing a single line of code, .NET provides you with a scalable and powerful
framework to code upon. Before I explain its benefits, let’s have a little discussion about how
exactly it works.
When a .NET application is compiled, it’s not compiled to machine code. Instead, .NET
applications are compiled to IL (Intermediate Language), which is akin to Java bytecode. When
the application is executed, it is then compiled into native executable code, which is managed by
the Common Language Runtime (CLR). What this management means to us as developers is that
the CLR can guarantee certain aspects of your application function, for example, garbage
collection and exception handling, giving it inherent robustness and security. This architecture is
known as Managed Code, and gives your applications a great deal of tolerance out of the box.
In ASP.NET, compilation is dynamic. .NET compiles its output when a page or resource
is first requested. Subsequent requests then use this compiled output to produce the resource,
resulting in extremely fast, compiled applications. This is why, when you first run an ASP.NET
application, there’s a short delay before the request is returned. So, don’t worry: things only get
faster…much faster!
The framework also includes the Microsoft Framework Classes, the largest and most
feature-rich set of ready-to-use classes Microsoft has ever released. The System classes, as
they’re known, can be employed by any .NET application, meaning the code you write for your
Website can just as easily be used within desktop applications or mobile devices (assuming
you’ve designed them correctly, that is!). This in turn makes your developments far more
productive, as writing for the Web can be just as simple as writing for the desktop.

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The System classes also provide distinct methods for performing certain tasks. As an
example,
let’s
say
we
need
to
send
an
email.
We
can
use
the System.Web.Mail.SmtpMail class to achieve this:

SmtpMail.Send("FROM","TO","SUBJECT","MESSAGE BODY");
Because we have a defined point of access to the mail service (in this case,
the SmtpMail class), any future changes or improvements to the code that sends mail is coordinated and our application will automatically benefit. Contrast this with ASP development,
for example, where there were many different implementations for sending an email, often using
COM. In addition, .NET’s co-ordination increases code readability. If we’re looking at a system
as a new developer, the SmtpMail class can easily be recognised and its functionality attributed
to it. Again, contrasted with ASP, where we’d need to recognise the particular COM object used
to gain an understanding of the code, this delivers considerable benefits.
Not only does the framework provide a reliable, managed method of writing and executing your
applications, it also helps co-ordinate your code. Not bad for something you get for free!
Object Orientated Architecture
Everything in .NET is an object. This means that everything you use and write is also an
object. In ASP.NET, for example, a Web page is treated as an object — even a tag can be treated
as an object. This yields a powerful means of accessing and controlling your Web applications as
you deal with properties to set and retrieve information, and respond to events occurring within
the application.
Let’s look at this in action. The code below sets the title of the Web page when it’s first
loaded, then changes the title when the user clicks on a button:

<%@ Page Language="C#" %>
<script runat="server">

void Button1_Click(object sender, EventArgs e)
{
titleTag.InnerText = "You clicked the button!";

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}

void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
titleTag.InnerText = "Page has loaded";
}

</script>
<html>
<head>
<title runat="server" id="titleTag"/>
</head>
<body>
<form runat="server">
<asp:Button id="Button1" OnClick="Button1_Click" runat="server"
Text="Button"/>
</form>
</body>
</html>
Notice that, to execute code when the page first loads, we place it within
the Page_OnLoad event, which is fired when the page is first requested. In procedural languages,
like ASP, this code would have been placed at the very beginning of the page to achieve a
similar result. By using events, however, we can very effectively organise our code and control
3


its execution. Hence, when the user clicks on the Button control placed on the page, the
Button’s OnClick event is fired, and our code executed.
The code also exposes the title tag of our page as an object that’s ready for us to use within our
code, by adding a runat="server" attribute to the tag, and giving it an ID. We can then access
the properties of this tag, in this case, InnerHTML to set its value. This makes accessing and
setting the output of pages easy to control.
This object orientation also means we have access to a wide range of encapsulated code and
functionality in the form of server controls. Just as in desktop development, you can drag and
drop controls onto your pages, set their appearance, location, and write code to fire on specific
events. The Button defined above is an example of a server control. .NET ships with a whole
host of powerful server controls, such as the DataGrid, which allows for powerful and refined
display of a wide range of data, and the Panel control, which lets you section your pages to hide
or display different groups of elements as appropriate.
All the rules of object orientation apply to controls too. In the same way that you can create
specialisations of classes, you can inherit the abilities of a control and add your own
functionality. The recent RSS DataList control tutorial highlights how easy this is to implement.
Caching
For total performance, ASP.NET includes a very powerful and easy to use caching system. Any
object can be sent to the cache for later retrieval, with total control on its life span. For example,
the code below fetches results from a database (see the section on Data Access later for more
information):

SqlConnection conn = new SqlConnection(connectionString);

SqlDataAdapter a = new SqlDataAdapter("select * from mytable;", conn);

DataSet s = new DataSet();

a.Fill(s);

4


We can cache the results (in this case, represented by a DataSet) of our query, so subsequent
requests will not need to connect to the database to complete the request. How easy is ASP.NET
caching? Take a look:

Cache["databasequery"] = s;
Once an object is stored within the cache, we can access it again in a similarly easy way:

s = (DataSet)Cache["databasequery"];
Before we access the cache however, it is important we first check there is something available
in the cache. So, introducing caching to our earlier code means only 3 extra lines of code:

if (Cache["databasequery"] == null) {
SqlDataAdapter a = new SqlDataAdapter("select * from mytable;",
conn);
a.Fill(s);
Cache["databasequery"] = s;
}
else
{
s = (DataSet)Cache["databasequery"];
}
ASP.NET can also cache complete pages. By adding a directive to the page, caching can be
controlled
by
a
parameter
(e.g.
http://mydomain.com/myresource.aspx?clearcache=true) or by the IP address of
the requestor, and a timeout for the cache can be set.
5


XML Configuration
Configuration of your ASP.NET applications is controlled by the use of a Web.config file.
Taking an XML format, this file is completely extendible, so you can effectively abstract
configuration settings (such as database connection strings) from your code. This improves the
administration and maintenance of your application by providing a central location for storing
information that may be needed by many of your resources.

Let's see this in action. The following XML is a snippet from a full Web.config specifying a
string containing the database connection string we'll use from our application:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<appSettings>
<add key="ConnectionString"
value="server=localhost;database=test;uid=sa;pwd=password;"
/>
</appSettings>
<system.web>
<customErrors mode="Off"/>
</system.web>
</configuration>
It should be noted that ASP.NET makes the Web.config file inaccessible through the
Web, which provides some security. However, storing sensitive information like connection
strings anywhere on your server in plain text might pose a security risk. In this case, you could
first encrypt the connection string before adding it to your Web.config file, and decrypting it
when it is required.

6


To access via our code a setting we've placed in the Web.config file, we use the following call:

connString = ConfigurationSettings.AppSettings("ConnectionString");
The value of the connection string can now be altered without changing or recompiling our code.

Code Separation
Anyone who's spent time hacking together inline scripts knows that changes to the
design of a page can alter the overall effect of an application. In combination with ASP.NET's
object model for Web pages, code-behinds separate code from the design of a page, leaving your
Web designers free to alter your designs without breaking your code.

A code-behind itself is just a file that contains the source code for a page, which is linked to the
Web page (HTML) through a declaration:

<%@ Page language="c#" Codebehind="WebForm1.aspx.cs"
Inherits="SitePoint.Webform1" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<head>
<title>WebForm1</title>
</head>
<body>
<form id="Form1" method="post" runat="server">
</form>
</body>
7


</html>
The code-behind file, here referenced as WebForm1.aspx.cs, must contain an
implementation for the object this page inherits, in this case defined as SitePoint.Webform1:

using System;

namespace SitePoint {
public class WebForm1 : System.Web.UI.Page {

private void Page_Load(object sender, System.EventArgs e) {
//code to run at page load
}
}
}

Mobile Support

Mobile devices are becoming an extremely popular method of accessing information on
the Web. .NET gives you the tools to support over 200 different mobile devices from a single
source base. Having analysed any device that requests your page, the Mobile Internet Toolkit
(MIT) automatically dishes out your pages in different mark-up (WML, HTML 3.0) and in
different form factors (screen size, card sizes) appropriate to the device in question.

8


This means that if we access our page through a WAP browser, we'd be served a WML
output, paginated to our mobile phone's display size and network connectivity. However, if we
accessed the very same page through a PDA, we'd be served an HTML output, with much more
information on each page taking into account of the extra features and larger screen size our
PDA has over the mobile phone.
Data Access
One area in which .NET really shines is that of its extendible data access components,
known as ADO.NET. ADO.NET provides a high level interface to virtually every database that
exists, with generic connectivity through ODBC and OLE DB, as well as specialised and
optimised connectivity for SQL Server, Oracle and MySQL (through a third party component).

With ADO.NET, all data is transported in XML, allowing for great interoperability
between data providers and applications. This also allows XML files to be used for data storage
using the same structures and access techniques as traditional databases.

ADO.NET uses a disconnected model, which means that applications work with data
locally, only contacting the server for data transfer or update. This means your application isn't
as reliant on the performance of the database, improving performance and the scalability of
applications by removing bottlenecks.

With these enhancements comes a productivity boost. While data access still isn't "plug
and play" -- that is, you still need to deal with SQL statements, data structures, and to a certain
extent, deal with your database -- it does introduce easy-to-use methods for accessing data. For
example, here's the code to pull a set of rows from a table on a running SQL Server and display
the first field in each row:


9


a.Fill(s);
foreach (DataRow dr in s.Tables[0].Rows)
{
Console.WriteLine(dr[0].ToString());
}
Anyone who's dealt with traditional ADO or other data access objects will notice how clean and
methodical the access is.

We can also, at any point, read and write XML from our DataSet using the ReadXML
and WriteXML methods. So, to extend the earlier example, we can now output the results of our
query in structured XML to a file fileName:


a.Fill(s);
s.WriteXml(fileName);

Language Preference
.NET is language neutral. As mentioned at the start of this article, all .NET compilers
interpret and compile your code to the same base language, IL (intermediate language, akin to
Java bytecode) to run on the CLR (Common Language Runtime). This means you can happily
use Visual Basic.NET and receive the same performance and functionality of those traditionally
more powerful languages like C++. In essence, you can choose the language you use.

10


As with spoken languages, the availability of information in the form of example
differs from language to language. While you may be able to read and express anything you
would wish to in Esperanto, to read the majority of content on the Web, you'll still need a decent
grasp of English. This is similar with .NET. You may choose Eiffel.NET as the language with
which to develop your applications, yet most examples and references you'll find will be coded
in either C# or VB.NET. To apply these to Eiffel, you'll need an understanding of these
languages as well.

So, what are the choices? C# is a language developed by Microsoft specifically for
.NET. Taking a similar syntax style to that of Java, C# is recognised as a clean, modern language
and, with its similarity to Java, is a great bridge from Java to .NET. Visual Basic .NET
(VB.NET) extends Visual Basic 6 to offer the power of object orientated programming within
.NET. In a nutshell, anyone who's already familiar with VB6 will have little problem moving up
to VB.NET.

Let's have a look at some example code: a class written in C#, and its equivalent in VB.NET:

namespace sitepoint.csharp
{
public class HelloWorld
{
public string sayHello(string name)
{
return "Hello "+name+"!";
}
}
}

Namespace sitepoint.visualbasic

11


Public Class HelloWorld
Function sayHello(ByVal name As String) As String
Return "Hello " + name + "!"
End Function
End Class
End Namespace
A single project can even use different classes for different files! This language
tolerance also means we can reuse code developed with different languages without the
headaches of the past. No marshalling, no COM, just transparent language interoperability
courtesy of .NET.

Web Services
Web services aren't new or unique to .NET. In fact, that is the whole point of a Web
service -- that it uses standards to enable cross-platform, cross-development execution of code.
However, the way in which .NET simplifies the creation of Web services is certainly a great
string in its bow.

A Web service is essentially a collection of methods that can be accessed via HTTP and
SOAP. You can, as with any method, have a custom object return type, or pass custom objects to
the method, which means you can distribute parts of your application very simply.

An example: below we have the Hello World example class used earlier in this article:

{
public class HelloWorld
{
12


{
}
}
}
At the moment, to use the sayHello method, we must use it within .NET and have the
compiled assembly available on our machine.

By exposing the method sayHello as a Web service, however, we can host the code
on a network, far away from our machine, and also allow developers of other languages (not
necessarily .NET languages!) to use our functionality.

Exposing the method as a Web method is simplicity itself. We just add a WebMethod attribute to
the method and inherit behavior from the WebService class:

using System.Web.Services;

{
public class HelloWorld: WebService
{
[WebMethod]
{

13


}
}
}
After linking this to a service page (a one-line instruction contained within a .asmx file), we have
exposed this method and its functionality on the Web, ready for all to use (or consume).

When you consume a Web service, you create a proxy class that contains the methods
exposed by the service, and define classes for the types used within the methods. This proxy
class means you can treat the Web service as if it were local to your application: it automatically
handles the remote calls to the service.

If you've identified functionality in your code that you feel could benefit from being
distributed (heavy computational tasks, for example), which could be sold as a service to third
parties, or which might require high levels of maintenance, Web services will help ease
deployment headaches while opening new avenues for sale. It's a win-win situation.

It's By Microsoft
This might be a point against .NET in your books, and if you're wishing to write crossplatform software, it certainly is. But whatever your personal view of the corporation, one fact
remains: Microsoft has the money to innovate and market their products like no one else in the
industry. This means that .NET isn't disappearing any time soon and, as with every Microsoft
development framework, there are heaps of freely available guides, ebooks and reference
libraries to help us developers.

Previews of Microsoft's next generation operating system Longhorn show how the
skills learnt from developing .NET today will be directly transferable to Longhorn development
tomorrow. This almost guarantees the worth of .NET skills for the foreseeable future, something
that's normally very difficult to say in the rapidly evolving computer industry.

Of course, with the positives come certain negatives, most principally the lack of full
cross-platform support with .NET. While there is nothing stopping .NET from making its way to
14


Linux technically (and projects like Mono show just how true this is), there is no drive from
Microsoft to support .NET on alternative operating systems, because of the obvious conflict of
interest with Windows, the market where Microsoft makes the bulk of its money. While this may
rule out .NET development for some, in reality, products like Windows Server 2003 now remove
many of the obstacles to Windows server adoption such as the concerns around security,
reliability and performance that existed in the past.

It's Cheap!
Not a statement that can be usually directed at Microsoft, particularly in comparison
with its open source rivals, but pound for pound, dollar for dollar, .NET offers great value for
money.

To get started with .NET, all you need is a box with a modern version of Windows installed
(ASP.NET requires IIS 5.0 or above, meaning Windows 2000 or XP Pro are required for serving
Web applications). The framework itself is free, and Microsoft's strong support for .NET means
a decent IDE in the form of Web Matrix is available for free; however, as with most
development frameworks, to write code, all you need is Notepad.

And, of course, there is the mighty Visual Studio .NET. By requiring a hefty license
fee, it can't be called cheap, but the productivity gains and project organisation it introduces
means Visual Studio .NET can pay for its license several times over in a single development
process.

As mentioned in the data access section of this article, .NET supports virtually every
database available today, including open source, freely available databases like MySQL.
However, Microsoft also has a free database in the form of MSDE, a developer edition of their
SQL Server database. While Microsoft still will not allow commercial use of the database,
MSDE provides a powerful, easy to administer database that can be directly scaled to SQL
Server.

For more information on where to get the components you need, and a comprehensive
guide on how to install them, see the first chapter of "Build Your Own ASP.NET Web Site
Using C# & VB.NET".

Prices for Web hosting have also been steadily decreasing since .NET's release. Large
hosts like InterLand and 1&1 now offer fully-featured .NET packages at similar prices to
traditional LAMP (Linux-Apache-MySQL-PHP) configurations.
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The Future
Microsoft is in no way finished with .NET yet. Whidbey, due for release next year,
includes countless enhancements and new additions, including object relational mapping,
simplified user management, themeing, and much more besides. Read the Preparing for Whidbey
article for more information on what to expect.

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