Hello World
To start learning ASP.NET, we will construct a very simple HTML page that will display "Hello World!" in an Internet browser like this:
| Hello World! |
Hello World in HTML
This code displays the example as an HTML page:
<html> |
If you want to try it yourself, save the code in a file called firstpage.html, and create a link to the file.
Hello World in ASP.NET
The simplest way to convert an HTML page into an ASP.NET page is to copy the HTML file to a new file with an .aspx extension.
This code displays our example as an ASP.NET page:
<html> |
If you want to try it yourself, save the code in a file called firstpage.aspx, and create a link to the file.
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.
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.
Dynamic Page in Classic ASP
To demonstrate how ASP can display pages with dynamic content, we have added some executable code (in red) to the previous example:
<html> |
The code inside the <% --%> tags is executed on the server.
Response.Write is ASP code for writing something to the HTML output stream.
Now() is a function returning the servers current date and time.
If you want to try it yourself, save the code in a file called dynpage.asp, and create a link to the file.
Dynamic Page in ASP .NET
This following code displays our example as an ASP.NET page:
<html> |
If you want to try it yourself, save the code in a file called dynpage.aspx, and create a link to the file.
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.
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