In the Introduction to this book, we listed the main motivations that Microsoft had when designing and developing ASP+. After all, considering that ASP has been so successful, why do we need a new version? There are really four main issues to consider:
Currently, ASP can only be scripted using the basic non-typed languages such as VBScript and JScript (unless you install a separate language interpreter). While ASP does parse and cache the code for the page the first time it is executed, the limitations prevent more strongly-typed languages like Visual Basic and C++ from being used where this would be an advantage. ASP+ provides a true language-neutral execution framework for Web applications to use.
It is also very easy to create huge ASP pages containing a spaghetti-like mixture of code, HTML, text, object declarations, etc. And it's hard to re-use code, unless you place it in separate 'include' files – not the best solution. In many environments, developing a Web application utilizes the skills of a wide range of professionals, for example, you have programmers writing the code, and designers making the HMTL look good. Having both the code and the content intermixed in a single file that both of these groups need to operate on makes it difficult for them to work together. ASP+ allows true separation of code and content.
In previous versions of ASP, you have to write code to do almost anything. Want to maintain state in form fields? Write code. Want to validate data entered on the client? Write code. Want to emit some simple data values? Write code. Want to cache regions of pages to optimize performance? Write code. ASP+ introduces a real component model, with server-based controls and an event driven execution paradigm similar in concept to the way that a Visual Basic 'Form' works now. The new ASP+ server controls are declarative (i.e. you only have to declare them in order to get them to do something), and so you actually write less code – in fact, in many situations you don't have to write any code at all!
The world out there is changing. The proportion of users on the Web that will access your site through an 'Internet device' such as a mobile cellular phone, personal digital assistant (PDA), TV set-top box, games console, or whatever else, will soon be greater that the number using a PC and a traditional Web browser. This means that we probably have to be prepared to do more work at the server to tailor our pages to suit a specific device. We'll also have to create the output in a whole new range of formats such as the Wireless Markup Language (WML). And, in addition to creating WML for rendering, new Internet devices and business applications are going to want to be able to send and receive XML data from Web applications. Doing this today from ASP requires you to manually use an XML parser, convert data to and from XML schemas, etc. ASP+ Web Services makes it much easier.
Besides all of this, the rapidly changing nature of distributed applications requires faster development, more componentization and re-usability, easier deployment, and wider platform support. New standards such as the Simple Object Access Protocol (SOAP), and new commercial requirements such as business-to-business (B2B) data interchange, require new techniques to be used to generate output and communicate with other systems. Web applications and Web sites also need to provide a more robust and scalable service, which ASP+ provides through proactive monitoring and automatic restarting of applications when failures, memory leaks, etc. are discovered.
So, to attempt to meet all these needs, ASP has been totally revamped from the ground up into a whole new programming environment. While there are few tools available to work with it just yet, Visual Studio 7.0 will be providing full support to make building ASP+ applications easy (both ASP+ Pages and ASP+ Services).
The rich, component based, event driven programming model is specifically designed to be 'tools friendly', and this support will be available for all Visual Studio languages – including VB, C++, and C#. And you can be sure that third party tool manufacturers will not be far behind.
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