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In this chapter, you got a brief history lesson on the methodologies for building user interfaces to servers that process your data and on the constantly swinging pendulum from thin client to fat client. You were brought up to date on what the newest trend in this development is—web-based thin clients with rich functionality thanks to the asynchrony delivered by the XMLHttpRequest object. This object is the core of Ajax, and in this chapter you built a simple demonstration that used it. This example was straightforward and barely scratched the surface of what you can do with Ajax; however, it demonstrated one of the drawbacks of using this methodology, namely, that it is heavy on the scripting. JavaScript, although powerful, is difficult and onerous to debug and manage when compared to languages such as C#, VB .NET, and Java. As such, the application benefits you receive by using an Ajax approach may be nullified by the application development getting bogged down in thousands (or more) lines of JavaScript.

It is with this problem in mind that Microsoft is attempting to bring the productivity of ASP.NET with Visual Studio 2005 to the Ajax space, and thus Atlas was born. In the next chapter, you’ll be introduced to the wonderful world of Atlas, you will look at the architecture of it, you will learn how it allows you to use Visual Studio 2005 and ASP.NET 2.0 controls to generate client-side code from server-side controls, and you will see how this can give you the best of Ajax while avoiding the worst of it.

In this chapter, you were introduced to the overall architecture of Atlas, and you went on a tour of the various features of this architecture and how Atlas can empower your development of richer browser-based clients. Atlas is based on two pillars: the script library, which encapsulates many common functions as well as provides an object-oriented API layer for JavaScript developers and proxies to network services, and the server extensions, which provide server-based controls that can be used to implicitly generate JavaScript code that uses the libraries to implement your application on the client but that can also be debugged and maintained as server-side web applications.

I also introduced the concepts of components and controls.

In addition, I introduced data binding and gave a simple demonstration of how to connect client applications directly to web services or other middleware. In addition, I showed how to use Atlas behaviors—browser-independent, JavaScript-based enhancements to UI elements that are implemented on those elements using attribution.

In the next chapter, you’ll see in more detail how Atlas makes JavaScript much easier. You’ll be introduced to the various libraries and how they create and present a unified design and coding framework with ASP.NET server pages. You’ll get an overview of the libraries and each of their functions and will learn about details such as the namespaces, inheritance, and various interfaces that these libraries offer you as a developer.

In this chapter, you began looking at the power of JavaScript in Atlas. You learned about the extensions to JavaScript implemented in the Atlas.js library that allow you to use true object orientation within your JavaScript, enabling such technologies such as inheritance, namespaces, and interfaces. Through hands-on coding, you saw how these features work and how you can use them to make JavaScript easier to code, debug, and maintain. Additionally, you looked at the JavaScript features that automatically encapsulate asynchronous web service calls from your browser application. You saw how to implement and consume a web service as well as how to wire up the asynchronous call to it. Comparing the complexity of this call to the Ajax code in Chapter 1, you can see it is accomplishing a more complex task (a SOAP call to a web service as opposed to a straight HTTP GET) with less code and in an easier-to-read and easier-to-maintain manner.

From here you can begin to see the value that Atlas brings to Ajax-style applications. In the following chapters, you will start looking into the libraries of controls that Atlas offers, including looking at the client-side controls in Chapters 4 and 5.

In this chapter, you started looking at client-side controls in Atlas, investigating the common HTML controls that are available as Atlas controls and how you can use and manipulate these using JavaScript or Atlas Script. These controls make the page-level manipulation of objects easier to handle, but they go far beyond just being a scripting methodology for existing functionality. With Atlas you can add new functionality to your client-side controls using behaviors, actions, data binding, and lots of user interface features such as drag and drop. In Chapter 5, you will take what you started with in this chapter and learn in more depth about how to use Atlas Script to associate this functionality with client-side controls.

This chapter intended to take you through many simple examples of using Atlas client-side controls and demonstrate how to implement and manipulate them using Atlas Script and JavaScript. It was intended to be very hands-on; in other words, you learned by doing. You went through 11 examples of different functionalities, using data binding, actions, behaviors, and more, to implement some complex GUI functionality.

You’ll get into more client controls and client functionality later in the book, particularly as you work through the full example in Chapter 12. However, now is a good time to put these new tools that you’ve learned into your pencil box and move onto the other side—the server side. In the next few chapters, you will start looking at implementing Atlas applications using the ASP.NET Atlas server-side controls.

This chapter introduced you to the server controls that are available to Atlas programmers. It walked you through using the ScriptManager control, which is at the heart of Atlas. This control empowers the download of the runtime as well as handles things such as error display messages. Additionally, you looked at the UpdatePanel control, which is at the heart of how Atlas enables Ajax functionality in existing ASP.NET pages using partial-page updates.

Other controls such as the Timer control and the UpdateProgress control are available on the server side to make your UI friendlier. Finally, you looked at some of the control extenders, which provide valuable client-side functionality to existing controls. The extenders are important in that they allow you to easily amend your existing ASP.NET applications unobtrusively. To extend ASP.NET controls for drag and drop, for example, you then simply add an extender to the page and point it at that control.

This chapter gave you a high-level overview of each control and how it works. In the next chapter, you will look at some applications and samples that use this functionality, as well as at the client-side controls you saw in Chapters 4 and 5, dissecting them to understand how you can program similar applications of your own in Atlas.

In this chapter, you started looking at client-side controls in Atlas, investigating the common HTML controls that are available as Atlas controls and how you can use and manipulate these using JavaScript or Atlas Script. These controls make the page-level manipulation of objects easier to handle, but they go far beyond just being a scripting methodology for existing functionality. With Atlas you can add new functionality to your client-side controls using behaviors, actions, data binding, and lots of user interface features such as drag and drop. In Chapter 5, you will take what you started with in this chapter and learn in more depth about how to use Atlas Script to associate this functionality with client-side controls.

This chapter intended to take you through many simple examples of using Atlas client-side controls and demonstrate how to implement and manipulate them using Atlas Script and JavaScript. It was intended to be very hands-on; in other words, you learned by doing. You went through 11 examples of different functionalities, using data binding, actions, behaviors, and more, to implement some complex GUI functionality.

You’ll get into more client controls and client functionality later in the book, particularly as you work through the full example in Chapter 12. However, now is a good time to put these new tools that you’ve learned into your pencil box and move onto the other side—the server side. In the next few chapters, you will start looking at implementing Atlas applications using the ASP.NET Atlas server-side controls.

This chapter introduced you to the server controls that are available to Atlas programmers. It walked you through using the ScriptManager control, which is at the heart of Atlas. This control empowers the download of the runtime as well as handles things such as error display messages. Additionally, you looked at the UpdatePanel control, which is at the heart of how Atlas enables Ajax functionality in existing ASP.NET pages using partial-page updates.

Other controls such as the Timer control and the UpdateProgress control are available on the server side to make your UI friendlier. Finally, you looked at some of the control extenders, which provide valuable client-side functionality to existing controls. The extenders are important in that they allow you to easily amend your existing ASP.NET applications unobtrusively. To extend ASP.NET controls for drag and drop, for example, you then simply add an extender to the page and point it at that control.

This chapter gave you a high-level overview of each control and how it works. In the next chapter, you will look at some applications and samples that use this functionality, as well as at the client-side controls you saw in Chapters 4 and 5, dissecting them to understand how you can program similar applications of your own in Atlas.

In this chapter, you looked at the Atlas libraries for mapping and how you can use them to build your own mapping applications. You looked at how to create and invoke an Atlas map on a page and how you can set its location using latitude and longitude. You looked at how to zoom in and out of a page programmatically and how to use its object model to move the map pane from place to place. Finally, you learned how to annotate the map using the built-in pushpin technology.

With all this in your toolbox, you can now start building your own mapping applications.