ASP.NET - HTML Server Controls

HTML server controls are HTML tags understood by the server.

HTML elements in ASP.NET files are, by default, treated as text. To make these elements programmable, add a runat="server" attribute to the HTML element. This attribute indicates that the element should be treated as a server control. The id attribute is added to identify the server control. The id reference can be used to manipulate the server control at run time.

ASP.NET - Server Controls

ASP.NET has solved the "spaghetti-code" problem described above with server controls.

Server controls are tags that are understood by the server.

There are three kinds of server controls:

• HTML Server Controls - Traditional HTML tags
• Web Server Controls - New ASP.NET tags
• Validation Server Controls - For input validation

Classic ASP

Active Server Pages (ASP) has been around for several years. With ASP, executable code can be placed inside HTML pages.

Previous versions of ASP (before ASP .NET) are often called Classic ASP.

ASP.NET is not fully compatible with Classic ASP, but most Classic ASP pages will work fine as ASP.NET pages, with only minor changes.

How Does it Work?

Fundamentally an ASP.NET page is just the same as an HTML page.

An HTML page has the extension .htm. If a browser requests an HTML page from the server, the server sends the page to the browser without any modifications.

An ASP.NET page has the extension .aspx. If a browser requests an ASP.NET page, the server processes any executable code in the page, before the result is sent back to the browser.

The ASP.NET page above does not contain any executable code, so nothing is executed. In the next examples we will add some executable code to the page to demonstrate the difference between static HTML pages and dynamic ASP pages.

ASP.NET vs Classic ASP

The previous examples didn't demonstrate any differences between ASP.NET and Classic ASP.

As you can see from the two latest examples there are no differences between the two ASP and ASP.NET pages.

In the next chapters you will see how server controls make ASP.NET more powerful than Classic ASP.

Classic ASP

Active Server Pages (ASP) has been around for several years. With ASP, executable code can be placed inside HTML pages.

Previous versions of ASP (before ASP .NET) are often called Classic ASP.

ASP.NET is not fully compatible with Classic ASP, but most Classic ASP pages will work fine as ASP.NET pages, with only minor changes.

New in ASP.NET

• Better language support
• Programmable controls
• Event-driven programming
• XML-based components
• User authentication, with accounts and roles
• Higher scalability
• Increased performance - Compiled code
• Easier configuration and deployment
• Not fully ASP compatible