I’ve been working with Microsoft and its technologies for many years now. Over the years,
I’ve seen Microsoft introduce all kinds of new technologies and initiatives: MS-DOS,
Windows, Windows CE, OLE, COM, ActiveX, COM+, Windows DNA, and so on. When I first

started hearing about Microsoft’s .NET initiative, I was surprised at how solid Microsoft’s
story seemed to be. It really seemed to me that they had a vision and a plan and that they
had rallied the troops to implement the plan.

contrast Microsoft’s .NET platform to ActiveX, which was just a new name given to good old
COM to make it seem more user friendly. ActiveX didn’t mean much (or so many developers
thought), and the term, along with ActiveX controls, never really took off. I also contrast
Microsoft’s .NET initiative to Windows DNA (Distributed InterNet Architecture), which was
another marketing label that Microsoft tacked onto a bunch of already existing technologies.
But I really believe in the Microsoft .NET initiative, and to prove it, I’ve written this book. So,
what exactly constitutes the Microsoft .NET initiative? Well, there are several parts to it, and
I’ll describe each one in the following sections.
An Underlying Operating System: Windows
Because these Web services and applications that use Web services run on computers and
because computers have peripherals, we still need an operating system. Microsoft suggests
that people use Windows. Specifically, Microsoft is adding XML Web serviceÐspecific
features to its Windows line of operating systems, and Windows XP and the servers in the
Windows .NET Server Family will be the versions best suited for this new service-driven
Specifically, Windows XP and the Windows .NET Server Family products have integrated
support for Microsoft .NET Passport XML Web service. Passport is a service that
authenticates users. Many Web services will require user authentication to access
information securely. When users log on to a computer running Windows XP or one of the
servers from the Windows .NET Server Family, they are effectively logging on to every Web
site and Web service that uses Passport for authentication. This means that users won’t
have to enter usernames and passwords as they access different Internet sites. As you can
imagine, Passport is a huge benefit to users: one identity and password for everything you
do, and you have to enter it only once!
n addition, Windows XP and the Windows .NET Server Family products have some built-in
support for loading and executing applications implementing the .NET Framework. Finally,
Windows XP and the Windows .NET Server Family operating systems have a new,
extensible instant messaging notification application. This application allows third-party
vendors (such as Expedia, the United States Postal Service, and many others) to
communicate with users seamlessly. For example, users can receive automatic notifications
when their flights are delayed (from Expedia) and when a package is ready to be delivered
(from the U.S. Postal Service).
don’t know about you, but I’ve been hoping for services like these for years—I can’t wait!
Helpful Products: The .NET Enterprise Servers
As part of the .NET initiative, Microsoft is providing several products that companies can
choose to use if their business logic (services) find them useful. Here are some of
Microsoft’s enterprise server products:
 §Microsoft Application Center 2000
 §Microsoft BizTalk Server 2000
 §Microsoft Commerce Server 2000
 §Microsoft Exchange 2000
 §Microsoft Host Integration Server 2000
 §Microsoft Internet Security and Acceleration (ISA) Server 2000
 §Microsoft Mobile Information Server 2002
Microsoft SQL Server 2000
t’s likely that each of these products will eventually have a “.NET” added to its name for
marketing purposes. But I’m also sure that over time, these products will integrate more
.NET features into them as Microsoft continues the initiative.
Microsoft XML Web Services: .NET My Services
Certainly, Microsoft wants to do more than just provide the underlying technologies that
allow others to play in this new world. Microsoft wants to play too. So, Microsoft will be
building its own set of XML Web services: some will be free, and others will require some
usage fee. Microsoft initially plans to offer the following .NET My Services:
 §.NET Alerts
 §.NET ApplicationSettings
 §.NET Calendar
 §.NET Categories
 §.NET Contacts
 §.NET Devices
 §.NET Documents
 §.NET FavoriteWebSites
 §.NET Inbox
 §.NET Lists
 §.NET Locations
 §.NET Presence
 §.NET Profile
 §.NET Services
These consumer-oriented XML Web services are known as Microsoft’s
“.NET My Services.” You can find out more information about them at
http://www.Microsoft.com/MyServices/. Over time, Microsoft will add many more consumer
services and will also be creating business-oriented XML Web services.
addition to these public Web services, Microsoft will create internal services for sales data
and billing. These internal services will be accessible to Microsoft employees only. I
anticipate that companies will quickly embrace the idea of using Web services on their
intranets to make internal company information available to employees. The implementation
of publicly available Internet Web services and applications that consume them will probably
proceed more slowly.
The Development Platform: The .NET Framework
Some of the Microsoft .NET My Services (like Passport) exist today. These services run on
Windows and are built using technologies such as C/C++, ATL, Win32, COM, and so on. As
time goes on, these services and new services will ultimately be implemented using newer
technologies, such as C# (pronounced “C sharp”) and the .NET Framework.
                        Even though this entire introduction has been geared toward building
                        Internet applications and Web services, the .NET Framework is
                        capable of a lot more. All in all, the .NET Framework development
                        platform allows developers to build the following kinds of applications:
                        XML Web services, Web Forms, Win32 GUI applications, Win32 CUI
                        (console UI) applications, services (controlled by the Service Control
                        Manager), utilities, and stand-alone components. The material
                        presented in this book is applicable to any and all of these application
presented in this book is applicable to any and all of these application
The .NET Framework consists of two parts: the common language runtime (CLR) and the
Framework Class Library (FCL). The .NET Framework is the part of the initiative that makes
developing services and applications really easy. And, most important, this is what this book
is all about: developing applications and XML Web services for the .NET Framework.
nitially, Microsoft will make the CLR and FCL available in the various versions of Windows,
including Windows 98, Windows 98 Second Edition, and Windows Me as well as Windows
NT 4, Windows 2000, and both 32-bit and 64-bit versions of Windows XP and the Windows
.NET Server Family. A “lite” version of the .NET Framework, called the.NET Compact
Framework, is also available for PDAs (such as Windows CE and Palm) and appliances
(small devices). On December 13, 2001, the European Computer Manufacturers Association
(ECMA) accepted the C# programming language, portions of the CLR, and portions of the
FCL as standards. It won’t be long before ECMA-compliant versions of these technologies
appear on a wide variety of operating systems and CPUs.
                      Windows XP (both Home Edition and Professional) doesn’t ship with the
                      .NET Framework “in the box.” However, the Windows .NET Server Family
                      (Windows .NET Web Server, Windows .NET Standard Server, Windows
                      .NET Enterprise Server, and Windows .NET Datacenter Server) will include
                      the .NET Framework. In fact, this is how the Windows .NET Server Family
                      got its name. The next version of Windows (code-named “Longhorn”) will
                      include the .NET Framework in all editions. For now, you’ll have to
                      redistribute the .NET Framework with your application, and your setup
                      program will have to install it. Microsoft does make a .NET Framework
                      redistribution file that you’re allowed to freely distribute with your
Almost all programmers are familiar with runtimes and class libraries. I’m sure many of you
have at least dabbled with the C-runtime library, the standard template library (STL), the
Microsoft Foundation Class library (MFC), the Active Template Library (ATL), the Visual
Basic runtime library, or the Java virtual machine. In fact, the Windows operating system
itself can be thought of as a runtime engine and library. Runtime engines and libraries offer
services to applications, and we programmers love them because they save us from
reinventing the same algorithms over and over again.
The Microsoft .NET Framework allows developers to leverage technologies more than any
earlier Microsoft development platform did. Specifically, the .NET Framework really delivers
on code reuse, code specialization, resource management, multilanguage development,
security, deployment, and administration. While designing this new platform, Microsoft also
felt it was necessary to improve on some of the deficiencies of the current Windows platform.
The following list gives you just a small sampling of what the CLR and the FCL provide:
 §Consistent programming model Unlike today, where some operating system
       facilities are accessed via dynamic-link library (DLL) functions and other facilities are
       accessed via COM objects, all application services are offered via a common object-
       oriented programming model.
 §Simplified programming model The CLR seeks to greatly simplify the plumbing and
       arcane constructs required by Win32 and COM. Specifically, the CLR now frees the
       developer from having to understand any of the following concepts: the registry, globally
       unique identifiers (GUIDs), IUnknown, AddRef, Release , HRESULTs, and so on. The
       CLR doesn’t just abstract these concepts away from the developer; these concepts
       simply don’t exist, in any form, in the CLR. Of course, if you want to write a .NET
       Framework application that interoperates with existing, non-.NET code, you must still be
       aware of these concepts.
Run once, run always All Windows developers are familiar with “DLL hell” versioning
problems. This situation occurs when components being installed for a new application
overwrite components of an old application, causing the old application to exhibit
strange behavior or stop functioning altogether. The architecture of the .NET
Framework now isolates application components so that an application always loads the
components that it was built and tested with. If the application runs after installation,
then the application should always run. This slams shut the gates of “DLL hell.”
  Simplified deployment Today, Windows applications are incredibly difficult to set up
and deploy. Several files, registry settings, and shortcuts usually need to be created. In
addition, completely uninstalling an application is nearly impossible. With Windows
2000, Microsoft introduced a new installation engine that helps with all these issues, but
it’s still possible that a company authoring a Microsoft installer package might fail to do
everything correctly. The .NET Framework seeks to banish these issues into history.
The .NET Framework components (known simply as types) are not referenced by the
registry. In fact, installing most .NET Framework applications requires no more than
copying the files to a directory and adding a shortcut to the Start menu, desktop, or
Quick Launch bar. Uninstalling the application is as simple as deleting the files.
  Wide platform reach When compiling source code for the .NET Framework, the
compilers produce common intermediate language (CIL) instead of the more traditional
CPU instructions. At run time, the CLR translates the CIL into native CPU instructions.
Because the translation to native CPU instructions is done at run time, the translation is
done for the host CPU. This means that you can deploy your .NET Framework
application on any machine that has an ECMA-compliant version of the CLR and FCL
running on it. These machines can be x86, IA64, Alpha, PowerPC, and so on. Users will
immediately appreciate the value of this broad execution if they ever change their
computing hardware or operating system.
  Programming language integration COM allows different programming languages
to interoperate with one another. The .NET Framework allows languages to be
integrated with one another so that you can use types of another language as if they are
your own. For example, the CLR makes it possible to create a class in C++ that derives
from a class implemented in Visual Basic. The CLR allows this because it defines and
provides a Common Type System (CTS) that all programming languages that target the
CLR must use. The Common Language Specification (CLS) describes what compiler
implementers must do in order for their languages to integrate well with other
languages. Microsoft is itself providing several compilers that produce code targeting
the runtime: C++ with Managed Extensions, C#, Visual Basic .NET (which now
subsumes Visual Basic Scripting Edition, or VBScript, and Visual Basic for Applications,
or VBA), and JScript. In addition, companies other than Microsoft and academic
institutions are producing compilers for other languages that also target the CLR.
  Simplified code reuse Using the mechanisms described earlier, you can create your
own classes that offer services to third-party applications. This makes it extremely
simple to reuse code and also creates a large market for component (type) vendors.
  Automatic memory and management (garbage collection) Programming requires
great skill and discipline, especially when it comes to managing the use of resources
such as files, memory, screen space, network connections, database resources, and so
on. One of the most common bugs is neglecting to free one of these resources,
ultimately causing the application to perform improperly at some unpredictable time.
The CLR automatically tracks resource usage, guaranteeing that your application never
leaks resources. In fact, there is no way to explicitly “free” memory. In Chapter 19,
“Automatic Memory Management (Garbage Collection),” I explain exactly how garbage
collection works.
  Type-safe verification The CLR can verify that all your code is type-safe. Type safety
ensures that allocated objects are always accessed in compatible ways. Hence, if a
method input parameter is declared as accepting a 4-byte value, the CLR will detect
and trap attempts to access the parameter as an 8-byte value. Similarly, if an object
occupies 10 bytes in memory, the application can’t coerce the object into a form that will
allow more than 10 bytes to be read. Type safety also means that execution flow will
transfer only to well-known locations (that is, method entry points). There is no way to
construct an arbitrary reference to a memory location and cause code at that location to
start executing. Together, these measures ensure type safety eliminating many
common programming errors and classic system attacks (for example, exploiting buffer
  Rich debugging support Because the CLR is used for many programming
languages, it is now much easier to implement portions of your application using the
language best suited to a particular task. The CLR fully supports debugging applications
that cross language boundaries.
  Consistent method failure paradigm One of the most aggravating aspects of
Windows programming is the inconsistent style that functions use to report failures.
Some functions return Win32 status codes, some functions return HRESULTs, and
some functions throw exceptions. In the CLR, all failures are reported via exceptions—
period. Exceptions allow the developer to isolate the failure recovery code from the
code required to get the work done. This separation greatly simplifies writing, reading,
and maintaining code. In addition, exceptions work across module and programming
language boundaries. And, unlike status codes and HRESULTs, exceptions can’t be
ignored. The CLR also provides built-in stack-walking facilities, making it much easier to
locate any bugs and failures.
  Security Traditional operating system security provides isolation and access control
based on user accounts. This model has proven useful, but at its core assumes that all
code is equally trustworthy. This assumption was justified when all code was installed
from physical media (for example, CD-ROM) or trusted corporate servers. But with the
increasing reliance on mobile code such as Web scripts, applications downloaded over
the Internet, and e-mail attachments, we need ways to control the behavior of
applications in a more code-centric manner. Code access security provides a means to
do this.
  Interoperability Microsoft realizes that developers already have an enormous amount
of existing code and components. Rewriting all this code to take full advantage of the
.NET Framework platform would be a huge undertaking and would prevent the speedy
adoption of this platform. So the .NET Framework fully supports the ability for the
developer to access their existing COM components as well as call Win32 functions in
existing DLLs.
Users won’t directly appreciate the CLR and its capabilities, but they will certainly notice the
quality and features of applications that utilize the CLR. In addition, users and your
company’s bottom line will appreciate how the CLR allows applications to be developed and
deployed more rapidly and with less administration than Windows has ever allowed in the

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