Web Application File Types

Typically, a web application can have different types of files serving different purposes. Some of the files are supported by ASP.NET, while others are supported by IIS. Most of them can be added to the web application by right-clicking the project in Solution Explorer, pointing to Add, and then clicking New Item.

File Type	Description
.aspx	An ASP.NET Web Forms file (page) that can contain web controls and presentation and business logic.
.ascx	A web user control file that defines a custom, reusable control.
.ashx	A generic handler file.
.config	A configuration file (typically Web.config) that contains XML elements that represent settings for ASP.NET features.
.master	A master page that defines the layout for other web pages in the application.
.svc	A WCF service file.
.asmx	An XML web services file that contains classes and methods that are available to other web applications by way of SOAP.
.axd	A handler file used to manage website administration requests, typically Trace.axd.
.resx	A resource file that contains resource strings that refer to images, localizable text, or other data.
.cs or .vb	Class source-code file that is compiled at run time.
Global.asax	A file that contains code that derives from the HttpApplication class. This file represents the application, and contains optional methods that run at the start or end of the application lifetime.