ASP.NET: An Introduction - ASP.NET (contd.)
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Web Services One great feature of ASP.NET are Web Services. Web services mean that you can literally have several pieces of your application on different servers all around the world, and the entire application will work perfectly and seamlessly. Web services can even work with normal .NET Windows applications.
For example: A lot of people would like to have a stock ticker on their web site, but not many people want to manually type in all changes to the prices. If one company (a stock broker) creates a web service and updates the stock prices periodically, then all of those people wanting the prices can use this web service to log in, run a function which grabs the current price for a chosen company, and return it. Web services can be used for so many things: news, currency exchange, login verification.. the ways in which they can be used are limited to your imagination!
Custom Controls In ASP.NET, you can create your own custom controls, along with those already provided. A good example of a custom control is a date selector. There are so many different date formats that validation of dates can become a pain, even more so if your visitor has to type in their date 5 times before it is accepted.
Instead of getting users to enter a date manually, we can let them use a date selector containing 3 drop down lists: day, month, and year. The day list has numbers 1-31, the month list has all of the month names, and the year list has a list of numbers from 1900 to 2050. The user now selects a day, month, and year, and your control returns that value in your specified format. You can even set a default value by passing a simple mm/dd/yyyy or dd/mm/yyyy date to the control before it is rendered.
Class Library ASP.NET includes an enormous class library which was built by Microsoft. Because this class library is so large, it encapsulates a a huge number of common functions. For example, if you wanted to retrieve data from a database and display that data in a simple grid control through classic ASP, then you'd have to write quite a lot of code.
In ASP.NET, you don't write any code to display the data: you just write the code to bind the data to an object called a DataGrid (which can be done in just a couple of lines). Then, you just have to create a reference on your page to where that DataGrid should go. The DataGrid will be rendered as a table, and will contain all of the data extracted from the database.
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