Parts of an ASP.NET Web Application

Web Forms or .aspx pages
Web Forms and .aspx pages provide the user interface for the Web application.

Code-behind pages
Code-behind pages are associated with Web Forms and contain the server-side code for the Web Form.

Configuration Files
Configuration files are XML files that define the default settings for the Web application and the Web server. Every Web application has one Web.config configuration file.

Global.asax File
Global.asax files contain the needed code for responding to application-level events that are raised by ASP.NET.

XML Web service links
XML Web srevice links allow the Web application to send and recieve data from an XML Web service.

Database connectivity
Database connectivity allows the Web application to transfer data to and from database sources.

Caching
Caching allow the Web application to return Web Forms and data more quickly after the first request.