.NET Framework
.NET Framework
The .NET Framework is the infrastructure for the new Microsoft .NET Platform.
The .NET Framework is a common environment for building, deploying, and running Web Services and Web Applications.
The .NET Framework contains common class libraries - like ADO.NET, ASP.NET and Windows Forms - to provide advanced standard services that can be integrated into a variety of computer systems.
The .NET Framework is language neutral. Currently it supports C++, C#, Visual Basic, JScript (The Microsoft version of JavaScript) and COBOL. Third-party languages - like Eiffel, Perl, Python, Smalltalk, and others - will also be available for building future .NET Framework applications.
The new Visual Studio.NET is a common development environment for the new .NET Framework. It provides a feature-rich application execution environment, simplified development and easy integration between a numbers of different development languages.
The .NET Framework is a new development platform that provides consistent and efficient support to distributed enterprise applications over local area networks (LANs) and the Internet. Key features of this new platform include the following:
• Provides a consistent language-independent, object-oriented development environment to leverage the developer's programming knowledge
• Provides hassle-free software deployment, avoiding versioning problems with related components
• Is a rich execution model, independent of storage location, where components can be stored and executed locally, or stored remotely and executed locally, or stored and executed remotely from an Internet location
• Provides safe code execution, with superior security settings to match the security needs of today's organizations
• Provides a consistent programming environment for both Windows and Web applications
• Improves execution performance of Windows and Web applications by efficient code compilation in both environments
• Is compliant with communication standards to ensure that .NET-connected applications can coexist and integrate with other applications and other platforms
The .NET Framework has two main components:
• The Common Language Runtime (CLR)
• The .NET Framework Class Library
The CLR is the system agent that runs and manages .NET code at runtime. This agent is responsible for basic system services such as memory management, threading, error control, and type safety.
Developers can use any .NET-compatible programming language to write their applications, and their particular compiler converts their code into Intermediate Language (IL) code. The CLR uses efficient Just In Time (JIT) compilation to convert language-independent IL code into machine code of the device on which the code is intended to run.
Managed code always runs in compiled mode and is optimized for the current platform; however, the code is still managed to prevent common execution errors. This new programming model offers tighter control over program execution, which provides a more robust platform on which to run distributed applications.
The .NET Framework Class Library is a comprehensive collection of object-oriented types that you can use to develop any application, service, or component. This class library supersedes the Microsoft Foundation Classes (MFC) commonly used in C++ development, and it is designed to be easily extensible to provide object-oriented programming support to other services, such as Microsoft Windows Server System products that currently provide proprietary-only Application Programming Interfaces (API).
The .NET Framework opens the door to sharing components over the Internet. The technology uses Web Services that can be consumed not only by Windows-based applications but also by applications running on other platforms if the applications use Internet standards such as TCP/IP, HTTP, XML, and SOAP.
Applications developed for the .NET Framework can still use COM components, which leverages the investment already made in previous developments. However, this compatibility comes with a performance cost due to the inherent translation between both standards. Therefore, the migration of COM components to managed code that .NET-connected applications use natively can greatly improve performance.
.NET Core Building Blocks
Web Services
Web Services provide data and services to other applications.
Future applications will access Web Services via standard Web Formats (HTTP, HTML, XML, and SOAP), with no need to know how the Web Service itself is implemented.
Web Services are main building blocks in the Microsoft .NET programming model.
More detail is avalibale at http://refreshskills.blogspot.com/2006/11/web-services.html
Internet Directory Services
.NET supports a new kind of directory services that can answer XML based questions about Internet Services, far more exactly than search engines and yellow pages.
These services are built on the UDDI standard.
Internet Storages
.NET offers secure and addressable places to store data and applications on the Web. Allowing all types of Internet devices (PCs, Palmtops, Phones) to access data and applications.
These Web Services are built on Microsoft's existing NTFS, SQL Server, and Exchange technologies.
Internet Calendar
.NET supports Internet integration of work, social, and private home calendars. Allowing all types of Internet devices (PCs, Palmtops, and Phones) to access the data.
These services are built on existing Outlook and Hotmail technologies.
Internet Dynamic Delivery
Reliable automatic upgrades by demand and installation independent applications.
.NET will support rapid development of applications that can be dynamically reconfigured.
Internet Identity
.NET supports many different levels of authentication services like passwords, wallets, and smart cards.
These services are built on existing Microsoft Passport and Windows Authentication technologies.
Internet Messaging
.NET supports integration of messaging, e-mail, voice-mail, and fax into one unified Internet Service, targeted for all kinds of PCs or smart Internet devices.
These services are built on existing Hotmail, Exchange and Instant Messenger technologies.
Standard Communication
Official Web standards (XML, UDDI, SOAP) will be used to describe what Internet data is, and to describe what Web Services can do.
Future Web applications will be built on flexible services that can interact and exchange data, without the loss of integrity.
.NET Framework Class Library
The .NET Framework class library is a collection of reusable types that tightly integrate with the common language runtime. The class library is object oriented, providing types from which your own managed code can derive functionality. This not only makes the .NET Framework types easy to use, but also reduces the time associated with learning new features of the .NET Framework. In addition, third-party components can integrate seamlessly with classes in the .NET Framework.
For example, the .NET Framework collection classes implement a set of interfaces that you can use to develop your own collection classes. Your collection classes will blend seamlessly with the classes in the .NET Framework.
As you would expect from an object-oriented class library, the .NET Framework types enable you to accomplish a range of common programming tasks, including tasks such as string management, data collection, database connectivity, and file access. In addition to these common tasks, the class library includes types that support a variety of specialized development scenarios. For example, you can use the .NET Framework to develop the following types of applications and services:
· Console applications.
· Windows GUI applications (Windows Forms).
· ASP.NET applications.
· XML Web services.
· Windows services.
For example, the Windows Forms classes are a comprehensive set of reusable types that vastly simplify Windows GUI development. If you write an ASP.NET Web Form application, you can use the Web Forms classes.
Client Application Development
Client applications are the closest to a traditional style of application in Windows-based programming. These are the types of applications that display windows or forms on the desktop, enabling a user to perform a task. Client applications include applications such as word processors and spreadsheets, as well as custom business applications such as data-entry tools, reporting tools, and so on. Client applications usually employ windows, menus, buttons, and other GUI elements, and they likely access local resources such as the file system and peripherals such as printers.
Another kind of client application is the traditional ActiveX control (now replaced by the managed Windows Forms control) deployed over the Internet as a Web page. This application is much like other client applications: it is executed natively, has access to local resources, and includes graphical elements.
In the past, developers created such applications using C/C++ in conjunction with the Microsoft Foundation Classes (MFC) or with a rapid application development (RAD) environment such as Microsoft® Visual Basic®. The .NET Framework incorporates aspects of these existing products into a single, consistent development environment that drastically simplifies the development of client applications.
The Windows Forms classes contained in the .NET Framework are designed to be used for GUI development. You can easily create command windows, buttons, menus, toolbars, and other screen elements with the flexibility necessary to accommodate shifting business needs.
For example, the .NET Framework provides simple properties to adjust visual attributes associated with forms. In some cases the underlying operating system does not support changing these attributes directly, and in these cases the .NET Framework automatically recreates the forms. This is one of many ways in which the .NET Framework integrates the developer interface, making coding simpler and more consistent.
Unlike ActiveX controls, Windows Forms controls have semi-trusted access to a user's computer. This means that binary or natively executing code can access some of the resources on the user's system (such as GUI elements and limited file access) without being able to access or compromise other resources. Because of code access security, many applications that once needed to be installed on a user's system can now be deployed through the Web. Your applications can implement the features of a local application while being deployed like a Web page.
Server Application Development
Server-side applications in the managed world are implemented through runtime hosts. Unmanaged applications host the common language runtime, which allows your custom managed code to control the behavior of the server. This model provides you with all the features of the common language runtime and class library while gaining the performance and scalability of the host server.
The following illustration shows a basic network schema with managed code running in different server environments. Servers such as IIS and SQL Server can perform standard operations while your application logic executes through the managed code.
Server-side managed code 
ASP.NET is the hosting environment that enables developers to use the .NET Framework to target Web-based applications. However, ASP.NET is more than just a runtime host; it is a complete architecture for developing Web sites and Internet-distributed objects using managed code. Both Web Forms and XML Web services use IIS and ASP.NET as the publishing mechanism for applications, and both have a collection of supporting classes in the .NET Framework.
XML Web services, an important evolution in Web-based technology, are distributed, server-side application components similar to common Web sites. However, unlike Web-based applications, XML Web services components have no UI and are not targeted for browsers such as Internet Explorer and Netscape Navigator. Instead, XML Web services consist of reusable software components designed to be consumed by other applications, such as traditional client applications, Web-based applications, or even other XML Web services. As a result, XML Web services technology is rapidly moving application development and deployment into the highly distributed environment of the Internet.
If you have used earlier versions of ASP technology, you will immediately notice the improvements that ASP.NET and Web Forms offer. For example, you can develop Web Forms pages in any language that supports the .NET Framework. In addition, your code no longer needs to share the same file with your HTTP text (although it can continue to do so if you prefer). Web Forms pages execute in native machine language because, like any other managed application, they take full advantage of the runtime. In contrast, unmanaged ASP pages are always scripted and interpreted. ASP.NET pages are faster, more functional, and easier to develop than unmanaged ASP pages because they interact with the runtime like any managed application.
The .NET Framework also provides a collection of classes and tools to aid in development and consumption of XML Web services applications. XML Web services are built on standards such as SOAP (a remote procedure-call protocol), XML (an extensible data format), and WSDL ( the Web Services Description Language). The .NET Framework is built on these standards to promote interoperability with non-Microsoft solutions.
For example, the Web Services Description Language tool included with the .NET Framework SDK can query an XML Web service published on the Web, parse its WSDL description, and produce C# or Visual Basic source code that your application can use to become a client of the XML Web service. The source code can create classes derived from classes in the class library that handle all the underlying communication using SOAP and XML parsing. Although you can use the class library to consume XML Web services directly, the Web Services Description Language tool and the other tools contained in the SDK facilitate your development efforts with the .NET Framework.
If you develop and publish your own XML Web service, the .NET Framework provides a set of classes that conform to all the underlying communication standards, such as SOAP, WSDL, and XML. Using those classes enables you to focus on the logic of your service, without concerning yourself with the communications infrastructure required by distributed software development.
Finally, like Web Forms pages in the managed environment, your XML Web service will run with the speed of native machine language using the scalable communication of IIS.
