What is ASP.NET?
In the past I worked very much with Active Server Pages (ASP) and everything was fine. Microsoft has since released a new technology called ASP.NET. In this Article I will try to explain the basics of ASP.NET. I will not only explain the theoretical part but I also will show you some practical "hello world " style examples. For these examples I will use C#, and VB.NET. I will try to answer all questions as good as I can. So take a cup of tea, have a seat on your favorite place and enjoy this article.
According to Microsoft it's sufficient to have a 133 MHz system with 128 MB of
RAM to use ASP.NET. For a better performance I recommend using at least Pentium II or III with 500 MHz and minimum 256 MB of RAM. You will also need the following software installed:
- Microsoft .NET Framework SDK ( Download from Microsoft )
- Microsoft Windows Component Update
- Internet Information Services 5 or 6
- Windows 2000 Professional with Service Pack 2 or
- Windows 2000 Server with Service Pack 2 or
- Windows XP Professional or
- Windows Server 2003
Note: You can develope ASP.NET pages on Win98/ME but to run these you will need a system with IIS 5 or 6.
Part I: What is ASP.NET?
With HTML you can only create static web pages, which used to be very useful and sufficed the needs in most cases. But as the Internet grows daily, and so do the demands of its users, you will soon need the ability to create dynamic pages, that react according to the action of the user. This, and much more, is possible with the help of ASP.NET.
ASP.NET can be used to make the Internet appear dynamical, faster and much more effective. Imagine you have a user called "Smith". You could write a dynamic ASP.NET page, which will greet the user according to the current time. In the morning, let's say from 6:00 AM to 11:00 AM you could greet Mr. Smith with something like: "Good Morning Mr. Smith. How are you ?" and from 12:00 PM to 18:00 PM with something like: "Good Afternoon Mr.Smith" and so on. I will show you the code for this example later.
In ASP.NET, similar to desktop applications, you can use variables, define functions and make use of a database, even a connection to a remote database is possible. In summary, ASP.NET is a programming system used to develop dynamic Web pages. This system provides the necessary technologies, like classes and objects, but yet it is not a programming language per se.
How does ASP.NET work?
For a better understanding on how ASP.NET works, I will first show you the traditional way that a Web page works (without ASP.NET).
1: Any internet user ( client ) is asking for
2: The Web-Server sends the physical content of the page back.
As you can see in the above image, calling a static page is very simple process. A client is asking/demanding for a Web page. For that you will need a connection between your client ( IE, Netscape etc.) and the server - this is done through the Internet. The file must exist on the server otherwise you will get a "404 File not found" error. The server reads the requested file and sends it back to the client. It doesn't matter who the client is or when the request reaches the server, the result will always be the same - until the file on the server is modified.
Now let us see how this will look with the usage of ASP.NET:
1: Any internet user ( Client ) is asking for
2: Server sends the inquiry to the ASP.NET engine.
3: ASP.NET creates the required new webpage for the user.
4: ASP.NET sends the created page back the Client.
The request of a dynamic Web page differs much from the static one. After the server has received the inquiry, it will be send to the ASP.NET engine. This checks whether the requested file exists. If the file exists, ASP.NET will not simply send the content back, instead it will create a new dynamic page that will be send back to the client. This dynamic page can look different from user to user.