ASP.Net Introduction
ASP.NET Microsoft "How Do I" Videos: http://www.asp.net/LEARN/videos/ - contains good intro to Visual Web Developer - for Logins ets
ASP.NET is a
web application framework
developed and marketed by
Microsoft to allow
programmers to build dynamic
web sites,
web applications and
web services. It was first released in January 2002 with
version 1.0 of the
.NET Framework, and is the
successor to Microsoft's
Active Server Pages (ASP)
technology. ASP.NET is built on the
Common Language Runtime
(CLR), allowing programmers to write ASP.NET code using any supported
.NET language.
After the release of Internet Information Services 4.0 in 1997, Microsoft began researching possibilities for a new web application model that would solve common complaints about ASP, especially with regard to separation of presentation and content and being able to write "clean" code.Mark Anders, a manager on the IIS team, and Scott Guthrie, who had joined Microsoft in 1997 after graduating from Duke University, were tasked with determining what that model would look like. The initial design was developed over the course of two months by Anders and Guthrie, and Guthrie coded the initial prototypes during the Christmas holidays in 1997.
The initial prototype was called
"XSP"; Guthrie explained in a 2007 interview that, "People would always
ask what the X stood for. At the time it really didn't stand for anything.
XML started with that; XSLT started with that. Everything cool seemed to
start with an X, so that's what we originally named it." The initial
prototype of XSP was done using
Java, but it was soon
decided to build the new platform on top of the
Common Language Runtime
(CLR), as it offered an
object-oriented programming
environment,
garbage collection and
other features that were seen as desirable features that Microsoft's
Component Object Model
platform didn't support. Guthrie described this decision as a "huge risk",
as the success of their new web development platform would be tied to the
success of the CLR, which, like XSP, was still in the early stages of
development, so much so that the XSP team was the first team at Microsoft to
target the CLR.
With the move to the Common Language
Runtime, XSP was re-implemented in
C# (known internally
as "Project Cool" but kept secret from the public), and renamed to ASP+, as
by this point the new platform was seen as being the successor to
Active Server Pages, and
the intention was to provide an easy migration path for ASP developers.
Mark Anders first demonstrated ASP+
at the ASP Connections conference in
Phoenix, Arizona on May 2, 2000. Demonstrations to the wide
public and initial beta release of ASP+ (and the rest of the .NET Framework)
came at the 2000
Professional Developers
Conference on July 11, 2000 in
Orlando, Florida. During
Bill Gates's keynote presentation,
Fujitsu demonstrated ASP+ being used in conjunction with
COBOL,
and support for a variety of other languages was announced, including
Microsoft's new
Visual Basic .NET and
C# languages, as well
as
Python and
Perl
support by way of interoperability tools created by
ActiveState.
Once the ".NET" branding was decided
on in the second half of 2000, it was decided to rename ASP+ to ASP.NET.
Mark Anders explained on an appearance on The MSDN Show that year
that, "The .NET initiative is really about a number of factors, it’s
about delivering software as a service, it's about XML and web services and
really enhancing the Internet in terms of what it can do .... we really
wanted to bring its name more in line with the rest of the platform pieces
that make up the .NET framework."
After four years of development, and
a series of beta releases in 2000 and 2001, ASP.NET 1.0 was released on
January 5, 2002 as part of version 1.0 of the
.NET Framework. Even prior to the release, dozens of books had
been written about ASP.NET, and Microsoft promoted it heavily as part of
their platform for web services. Guthrie became the product unit manager for
ASP.NET, and development continued apace, with version 1.1 being released on
April 24, 2003 as a part of
Windows Server 2003. This
release focused on improving ASP.NET's support for mobile devices.
.NET pages, known officially as "web
forms", are the main building block for application development.Web forms are contained in files with an ".aspx"
extension; in programming jargon, these files typically contain static (X)HTML markup, as well as markup defining server-side Web
Controls and User Controls where the developers place all the required
static and dynamic content for the web page. Additionally, dynamic code
which runs on the server can be placed in a page within a block <% --
dynamic code -- %> which is similar to other web development technologies
such as
PHP,
JSP, and
ASP, but this practice is
generally discouraged except for the purposes of
data binding since it
requires more calls when rendering the page.
ASP.NET aims for performance benefits
over other script-based technologies (including Classic ASP) by compiling
the server-side code to one or more
DLL
files on the
web server. This compilation happens
automatically the first time a page is requested (which means the developer
need not perform a separate compilation step for pages). This feature
provides the ease of development offered by scripting languages with the
performance benefits of a compiled binary. However, the compilation might
cause a noticeable but short delay to the web user when the newly-edited
page is first requested from the web server, but won't again unless the page
requested is updated further.
The ASPX and other resource files are
placed in a virtual host on an
Internet Information Services
server (or other compatible ASP.NET servers; see Other Implementations,
below). The first time a client requests a page, the .NET framework parses
and compiles the file(s) into a .NET assembly and sends the response;
subsequent requests are served from the DLL files. By default ASP.NET will
compile the entire site in batches of 1000 files upon first request. If the
compilation delay is causing problems, the batch size or the compilation
strategy may be tweaked.