An ASP.NET page consists of, at a minimum, a single file with an extension of .aspx, though typically, other files will be associated with the page, as we will describe later. In the parlance of Visual Studio 2008 (VS2008), this .aspx file is called the content file, because it contains primarily the visual content of the page, that is, HTML, text, and ASP.NET server controls.
Do not confuse the content file nomenclature, as used in this context, with the use of the same term when talking about master pages, where the content file is replaceable content that is inserted onto a master page. We use the terms markup page and code-behind file to help prevent confusion. We cover master pages in Chapter 13.
Any content in the content file that is not part of a server control or server-side code is treated as normal HTML markup. It is passed from the server to the browser exactly as is, so the browser can deal with it as it would any other HTML.
When a ...