Getting Started with ASP.NET

Overview The Microsoft .NET Framework provides a powerful platform for the development of applications for both the desktop and the Internet. The .NE T Framework allows you to develop Internet applications with an ease that was never provided before. To develop Internet applications, the .NET Framework is equipped with ASP.NET. ASP.NET is a powerful programming framework for the development of enterprise-class Web applications. This chapter introduces you to the .NET Framework and ASP.NET. You'll learn to set up the development environment for creating ASP.NET applications. You'll also learn how to create an ASP.NET application by using Visual Basic .NET and C#, and deploy the application.

Introducing the .NET Framework Since 1995, Microsoft has been constantly making efforts to shift focus from the Windows -based platforms to the Internet. Microsoft introduced Active Server Pages (ASP) as an endeavor toward Internet programming. However, writing ASP script, an interpreted script, was a traditional way of programming as compared to the existing structured object-oriented programming. Moreover, it was very difficult to debug and maintain the unstructured ASP code. Definitely, you could combine the code written in structured object-oriented languages, such as Visual Basic, with ASP code. However, you could combine the VB code only as a component. Moreover, the software integration for the Web development was quite complicated and required an understanding of a host of technologies and integration issues on the part of the developers. Therefore, an architecture was needed that would allow the development of Web applications in a more structured and consistent manner. Recently, Microsoft introduced the .NET Framework with a vision for developers to create globally distributed software with Internet functionality and interoperability. The .NET Framework includes multiple languages, class libraries, and a common execution platform. In addition, the .NET Framework includes protocols that allow developers to integrate software over the Internet and the .NET Enterprise Servers, such as SQL Server 2000, Commerce Server 2000, and BizTalk Server. Thus, the .NET Framework provides the richest built-in functionality for software integration ever provided by any platform. Also, with the .NET Framework, developing the Internet applications is as easy as developing desktop applications. The .NET Framework frees the software developer from most of the operating system specifics, such as memory management and file handling, because the .NET Framework covers all the layers of software development above the operating system. Figure 2-1 describes the different components of the .NET Framework. Figure 2-1: The .NET Framework The top layer represents user and program interfaces, and includes Windows Forms, Web Forms, Web Services, and Application Services. Windows Forms provide a Win32- based user interface. Web Forms provide a Web-based user interface. Web Services are the most revolutionary program interfaces because they allow programs to communicate over the Internet. The Internet-based program interfaces, which include Web Forms and Web Services, are implemented by ASP.NET, which is a built-in component of the .NET Framework. The middle layer represents the .NET Framework classes, which are universally available across multiple languages. The usage of these classes is consistent across all languages included in the .NET Framework. The base layer represents the common execution platform called the Common Language Runtime (CLR). This is the most important component of the .NET Framework. The CLR provides support for multiple languages and allows crosslanguage inheritance. For example, you can inherit a class written in Visual Basic from a class written in Visual C++. Thus, with .NET, the choice of a programming language simply depends on the user's choice. With .NET, it is possible to create applications by using multiple languages. The multiple-language support is possible because the CLR provides a common system of data types. In addition, the CLR performs the memory management and monitors the complete life cycle of objects, while it tracks objects and handles garbage collection. Visual Studio .NET (VS.NET) is the first release of the products based on the .NET Framework. It includes Visual Basic, Visual C++, and C#. VS.NET provides a common Integrated Development Environment (IDE) for all languages. Therefore, developers always work in a consistent environment irrespective of the language they use. With that basic understanding of the .NET Framework, you are ready to look at the basic features of ASP.NET. Introducing ASP.NET ASP.NET, the next version of ASP, is a programming framework that is used to create enterprise-class Web applications. The enterprise-class Web applications are accessible on a global basis, leading to efficient information management. However, the advantages that ASP.NET offers make it more than just the next version of ASP. ASP.NET is integrated with Visual Studio .NET, which provides a GUI designer, a rich toolbox, and a fully integrated debugger. This allows the development of applications in a What You See is What You Get (WYSIWYG) manner. Therefore, creating ASP.NET applications is much simpler. Unlike the ASP runtime, ASP.NET uses the Common Language Runtime (CLR) provided by the .NET Framework. The CLR is the .NET runtime, which manages the execution of code. The CLR allows the objects, which are created in different languages, to interact with each other and hence removes the language barrier. CLR thus makes Web application development more efficient. In addition to simplifying the designing of Web applications, the .NET CLR offers many advantages. Some of these advantages are listed as follows. § Improved performance: The ASP.NET code is a compiled CLR code instead of an interpreted code. The CLR provides just-in-time compilation, native optimization, and caching. Here, it is important to note that compilation is a two-stage process in the .NET Framework. First, the code is compiled into the Microsoft Intermediate Language (MSIL). Then, at the execution time, the MSIL is compiled into native code. Only the portions of the code that are actually needed will be compiled into native code. This is called Just In Time compilation. These features lead to an overall improved performance of ASP.NET applications. § Flexibility: The entire .NET class library can be accessed by ASP.NET applications. You can use the language that best applies to the type of functionality you want to implement, because ASP.NET is language independent. § Configuration settings: The application-level configuration settings are stored in an Extensible Markup Language (XML) format. The XML format is a hierarchical text format, which is easy to read and write. This format makes it easy to apply new settings to applications without the aid of any local administration tools. § Security: ASP.NET applications are secure and use a set of default authorization and authentication schemes. However, you can modify these schemes according to the security needs of an application. In addition to this list of advantages, the ASP.NET framework makes it easy to migrate from ASP applications. Before you start with your first ASP.NET application, take a quick look at how to set up the development environment, described next.