Lesson 2: Using ASP.NET

The purpose of this lesson is to detail the parts of an ASP.NET application, which introduces the ASP.NET Web form. The components of the web form ultimately come from the .NET Framework and its featured languages C# and VB.NET. It follows that a summary of the .NET Framework Class Library is supplied and a detailed comparison of C# and VB.NET syntax is in order. More information about these syntax differences can be found at MSDN under "Language Equivalents" here:

http://msdn.microsoft.com/library/en-us
    /vsintro7/html/vxgrfLanguageEquivalents.asp

The ASP.NET web application is made up of three parts: content, program logic and configuration information. The content is any recognizable MIME type (data recognized by the Multipurpose Internet Mail Extensions protocol). The program logic is a .NET assembly or a client-side script. The configuration information is stored in CSS files, the ASP.NET Web Application Configuration file and in IIS configuration stores.

For detailed information about MIME types start with the RFC1341 specification (which leads to the RFC 1521 and RFC 1522 standards) here:

http://www.w3.org/Protocols/rfc1341/0_Abstract.html

The detailed information about ASP.NET program logic starts with understanding the ASP.NET page, featuring the Web form and the sketch of its lifecycle presented in three stages: (i) IIS starting or getting the ASP.NET worker process (aspnet_wp.exe) to load the assembly associated with the Web form; (ii) the assembly composing a response based on the three parts of the ASP.NET web application; (iii) IIS returning the response to the user/requestor in the MIME type specified (text/html by default).

This lesson refers to Chapter 2, Lesson 2 for more details about this process. Dino Esposito further details this sequential, cyclical process in "The ASP.NET Page Object Model: One Day in the Life of an ASP.NET Web Page" here:

http://msdn.microsoft.com/library/en-us
    /dnaspp/html/aspnet-pageobjectmodel.asp

Web forms contain four types of components: (i) Server controls, (ii) HTML controls, (iii) Data controls like those of ADO.NET and (iv) System components like the FileSystemWatcher, EventLog and MessageQueue types.

More detailed information about ASP.NET program logic, Web forms and Web form components lead to the description of how a .NET application runs. The .NET application runs by compiling .NET languages, defining versioning and types, into MSIL (Microsoft Intermediate Language) in an assembly (a *.DLL file). This assembly is dynamically registered by the CLR (Common Language Runtime) which manages the running assembly, centralizing tasks like memory usage tracking essential in "Garbage Collection." It follows that a .NET application is called "managed code" so we can now refer to unmanaged code from DLL hell (usually a COM-based application statically registered in the Windows Registry).

The detailed information about ASP.NET Web application configuration appears in Chapter 9, Lesson 1. For an overview of IIS configuration, see "About IIS Configuration" here:

http://msdn.microsoft.com/library/en-us
    /iissdk/iis/about_iis_configuration.asp

The detailed MSDN information about client-side scripting survives under "Microsoft Windows Script Technologies" here:

http://msdn.microsoft.com/library/en-us
    /script56/html/vtoriMicrosoftWindowsScriptTechnologies.asp

The detailed MSDN information about CSS remains under "Cascading Style Sheets" here:

http://msdn.microsoft.com/library/default.asp?
    url=/workshop/author/css/css_node_entry.asp