Programming Visual Basic .NET

Chapter 6. ASP.NET and Web Forms: Developing Browser-Based Applications

ASP.NET is a technology for developing dynamic web pages. It has evolved from Microsoft’s ASP technology, so experience with ASP transfers fairly well to ASP.NET. While I don’t assume in this chapter that you have such experience, I do assume that you have at least a passing familiarity with HTML.

ASP.NET works with Microsoft’s Internet Information Services (IIS) to dynamically create HTML content so it can be sent to a web browser. This technology supports all browsers, because ASP.NET runs entirely on the server and sends only HTML (and, optionally, client-side JavaScript) to the browser.

With ASP.NET, web browsing works like this:

1. A user enters a web page address into a browser (or links to the address from another web page). For example, http://www.gotdotnet.com/default.aspx.

2. The browser sends a request to the server (in this case, www.gotdotnet.com), asking for the given web page (in this case, default.aspx).

3. The server receives the request and attempts to fulfill it. How the server fills the request depends on the type of page requested, as indicated by the filename extension. Files with an .html or .htm extension are assumed to contain plain HTML text and are sent to the browser as is. Files with an .aspx extension are assumed to contain ASP.NET application code and are therefore compiled and executed. Executing the ASP.NET code usually results in generating HTML content and sending it to the browser. ...