Over the years, we developers have seen many changes in terms of how development occurs. We have gone from terminal-based... more

Over the years, we developers have seen many changes in terms of how development occurs. We have gone from terminal-based programming to PC-based programming to Windows-based programming and to the Web. Now we are on the verge of another programming revolution—one that will bring about more interactive user interfaces to web applications. This programming revolution is brought to developers courtesy of a set of technologies that are generally known as AJAX (Asynchronous JavaScript And XML). No longer will users see the annoying flash with the clicking of a button to submit data. No longer will users lose the context of where they are located and be thrown back up to the top of a page. With AJAX, developers can build applications that step out of the traditional postback model of the Web, provide an improved user interface to users, and allow developers to develop applications that are much friendlier to use.

This chapter looks at the following:

• ASP.NET development and how it led to AJAX

• What AJAX is and a high-level overview of some of its base technologies

• The advantages of AJAX

• What ASP.NET AJAX is

• Some things that it might not make sense to do with AJAX

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ASP.NET AJAX installs templates that make it quick and easy to create new web applications that leverage its features. In... more

ASP.NET AJAX installs templates that make it quick and easy to create new web applications that leverage its features. In addition, it is fairly straightforward to update existing ASP.NET applications to allow them to support ASP.NET AJAX controls and functionality. The biggest challenge in setting up an application to use ASP.NET AJAX involves adding a number of settings to the web.config file. In the case of a new application, project templates are installed with the ASP.NET AJAX installation to make this task easy. For existing applications, follow the steps in this chapter to ensure they are properly configured to take advantage of ASP.NET AJAX’s features.

In this chapter, you learn about the following:

• Installing ASP.NET AJAX

• Creating an ASP.NET AJAX application

• Adding ASP.NET AJAX to an existing ASP.NET application

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ASP.NET AJAX has a unique, yet familiar architecture that builds on the foundations of ASP.NET 2.0 to strengthen its weak... more

ASP.NET AJAX has a unique, yet familiar architecture that builds on the foundations of ASP.NET 2.0 to strengthen its weak points. This chapter begins by discussing those weak points and describing how ASP.NET AJAX strengthens ASP.NET with powerful new features.

In this chapter you also learn key conceptual details about the ASP.NET AJAX framework, including client-side and server-side development and configuration details. Before you build a house (or a web site), you should have a solid foundation, and this chapter provides you with the foundational details you need to become a skilled ASP.NET AJAX developer.

Specifically, this chapter covers a variety of topics, including:

• Analyzing the foundations of ASP.NET AJAX

• Understanding the code library

• Working with the compatibility layer

• Exploring the Microsoft AJAX Library

• Stepping through the client-side event life cycle

• Investigating server-side components and controls

• Learning about the JavaScript files that get downloaded to the client

• Understanding how handlers are used

• Working with ASP.NET AJAX web.config files

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Calling web services is an important part of AJAX. Web services are the base mechanism used to transmit data between the... more

Calling web services is an important part of AJAX. Web services are the base mechanism used to transmit data between the client and the browser without the need for a postback. Calling a web service instead of performing a postback has several advantages, including less network traffic and generally higher performance.

Microsoft’s ASP.NET AJAX framework provides mechanisms that allow for AJAX-style operations. With this type of support, asynchronous commands can be sent between the client web browser and the web server. This communication is made through web services. This chapter looks at the following topics:

• Understanding AJAX

• Using client-side JavaScript

• Sending and receiving data with client-side JavaScript

• Setting up web services to be called

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The... more

The UpdatePanel is absolutely the coolest control included in the ASP.NET 2.0 AJAX Extensions 1.0. The UpdatePanel provides support for implementing AJAX-style operations by integrating the server-side development methodology that is well known to ASP.NET developers with the client-side AJAX development paradigm.

This chapter looks at the following topics:

• What the UpdatePanel is

• How the UpdatePanel works

• How to provide full support for all browsers through the UpdatePanel

• The client-side web page life cycle

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The ASP.NET AJAX Control Toolkit is a community project initiated by Microsoft that provides a set of controls based around... more

The ASP.NET AJAX Control Toolkit is a community project initiated by Microsoft that provides a set of controls based around the Microsoft AJAX Library and AJAX ASP.NET 2.0 Extensions 1.0. These controls are free for use within your own applications and provide features and behaviors far beyond those supplied in the Microsoft AJAX Library and ASP.NET 2.0 Extensions 1.0. You can think of the Microsoft AJAX Library and ASP.NET 2.0 Extensions 1.0 as the core framework (much like the .NET framework base class library itself), and the ASP.NET AJAX Control Toolkit as a set of controls built on top of that framework (much like the ASP.NET server-based controls or Windows Forms–based controls).

The Control Toolkit is a lot more than just a reusable set of controls, however. Complete with IntelliSense and designer support, it also provides a framework for building your own AJAX extender controls, and alleviates much of the common coding required to implement server-based controls.

It provides comprehensive cross-browser support, much like the ASP.NET 2.0 AJAX Extensions 1.0 and AJAX Library itself. Internet Explorer, Firefox, and Safari are among the major browsers supported with support for browsers such as Opera included where possible.

This chapter covers exactly what the Control Toolkit is from a community project perspective, examines controls within the Toolkit, and also covers the controls provided for developers wishing to create their own extender controls using the Control Toolkit. Specifically, you learn about the following topics:

• What a community project managed by Microsoft really means

• How to install the Control Toolkit

• What an extender control is

• How the controls within the Control Toolkit can be used

• What features and support the Control Toolkit provides for developers wishing to create their own extender controls

• How you can contribute to the Control Toolkit project

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In the previous chapter, you saw how the ASP.NET AJAX Toolkit controls utilized the concept of an extender control to augment... more

In the previous chapter, you saw how the ASP.NET AJAX Toolkit controls utilized the concept of an extender control to augment the behavior of existing controls within your application. An extender control is typically targeted at another control, and provides enhanced functionality for that control, and perhaps other controls as well.

There are really two types of controls that form the basis of the control set within ASP.NET AJAX 2.0 Extensions: script controls and extender controls. Both form part of the core framework of ASP.NET 2.0 AJAX Extensions.

Script controls are standalone controls that define their own behavior and operate independently of other controls (although often in conjunction with other controls). A good example of this is the UpdatePanel or the Timer control.

Extender controls operate in tandem with at least one other control on a page, and extend the functionality of that control. You saw this concept demonstrated extensively in Chapter 6 on the AJAX Control Toolkit. A good example is the TextboxWatermarkExtender that ships with the Toolkit, which extends a regular Textbox control. You saw how extender controls can be used within your applications in various ways to achieve rich, dynamic behavior, often without the need to write any JavaScript code.

This chapter details concepts and techniques required to build your own extender controls and provide reusable custom behavior for your AJAX applications. Specifically, this chapter covers:

• Extender control features within the core framework

• Building your own extender control using only the core functionality of ASP.NET 2.0 AJAX Extensions

• The enhanced framework and features provided by the AJAX Control Toolkit for building extender controls

• Building the same extender control using the AJAX Control Toolkit

• Advantages and disadvantages of both approaches

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JavaScript is a very simple language for adding functionality to a web browser application. However, it is lacking in several... more

JavaScript is a very simple language for adding functionality to a web browser application. However, it is lacking in several areas that formal programmers consider important. With the introduction of ASP.NET AJAX, Microsoft has added enhancements for JavaScript, and these enhancements address the perceived shortcomings in JavaScript. Some of the enhancements you look at in this chapter include the following:

• Extended support for basic data types, such as numbers and strings.

• The creation of namespaces and classes.

• The notion of inheritance and interfaces.

Note

JavaScript has no concept of private members. There will be properties shown whose name starts with an underscore (_), and these properties are considered to be private. As a result, you should not use them in your code even though you can access them.

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This chapter explains what the Microsoft AJAX Library is and how to use some of the classes. It goes over some of the more... more

This chapter explains what the Microsoft AJAX Library is and how to use some of the classes. It goes over some of the more useful features of the Library you might use more often than others. The examples are going to be mostly in JavaScript because the way you call these from VB and C# is nearly identical. In fact, the only real difference is the first line of code in your .aspx page:

<%@ Page Language="C#" %>

or

<%@ Page Language="VB" %>.

The Microsoft AJAX Library is a set of classes that provide a rich framework that greatly simplifies web client programming with JavaScript. It contains several namespaces that are very helpful in creating clean client code that very much feels like what you are familiar with in C#. This chapter consists of a list and description of each namespace and class and then goes into several of the classes in the Sys.* namespaces. The “The Sys Namespace” section explains how to use a few of the popular classes including the Sys.EventHandler class and the Sys.Debug class, among others. The “The Sys.Net Namespace” section explains how to use the popular networking classes and how to manage communication between Microsoft ASP.NET AJAX client applications and web services on the server. The final section, “The Sys.Serialization Namespace,” explains how and when you might want to serialize JavaScript types into JSON-formatted data.

In this chapter, you take a look at the following:

• A description of all the namespaces in the client library

• Which classes make up the Sys namespace

• Examples using the Sys.StringBuilder class

• How the underlying Sys.WebRequest class works

• JavaScript serialization

• Event handling in the Microsoft AJAX Library

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By this point in the book you should have a good understanding of how ASP.NET 2.0 AJAX makes it easy to provide functionally... more

By this point in the book you should have a good understanding of how ASP.NET 2.0 AJAX makes it easy to provide functionally enhanced user interfaces to end users. This chapter focuses more on the visual enhancements that ASP.NET 2.0 AJAX provides and explains how they work. It just so happens that one of the best visual enhancements is also one of the best functional enhancements. ASP.NET AJAX asynchronous postbacks are not only useful and efficient, but also pleasing to the eye. With a little effort, however, they can be made even more pleasing. Here’s a summary of the topics covered in this chapter:

• Understanding the differences between asynchronous and synchronous postbacks

• Notifying users during asynchronous postbacks

• Using the UpdatePanelAnimation extender

• Providing feedback during ongoing operations

• Aborting operations

• Handling exceptions gracefully

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Some of the most valuable features of ASP.NET 2.0 are the Membership and Profile services APIs. Saving developers countless... more

Some of the most valuable features of ASP.NET 2.0 are the Membership and Profile services APIs. Saving developers countless hours of development time, these services are an extensible foundation for identifying and authorizing users of a web application and persisting personal preferences. This chapter teaches you how to use Microsoft ASP.NET 2.0 AJAX integration with ASP.NET services to provide AJAX-style login and user-customized experiences.

The following topics are covered in this chapter:

• How to enable your site for AJAX support of ASP.NET application services

• How to use Microsoft ASP.NET 2.0 AJAX to build login, logout, and profile features for your web site

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So you have written your first ASP.NET AJAX application or you have upgraded an existing web site to utilize some features... more

So you have written your first ASP.NET AJAX application or you have upgraded an existing web site to utilize some features of ASP.NET AJAX and it all works straight away, without issue, right? Unfortunately, this is rarely the case, and at some point in time in any form of application development, AJAX or otherwise, you need to debug your application.

Debugging is the art of identifying and removing problematic code within your applications. Every developer has been required to perform some degree of debugging within their applications, at some point in time.

ASP.NET is predominately a server-side development technology and support for debugging of applications within ASP.NET is quite extensive. ASP.NET AJAX applications introduce some new aspects, which in turn introduce some new debugging challenges. The extensive use of JavaScript, and the fact that custom data may be transferred through the use of asynchronous postbacks, means that attention needs to be paid to these significant areas to deal with the challenges that are introduced when debugging AJAX-type applications with ASP.NET.

This chapter examines the various aspects of debugging ASP.NET AJAX applications and covers the following topics:

• General server-side ASP.NET debugging

• General JavaScript debugging

• Specific debugging support provided by the ASP.NET AJAX Extensions

• HTTP debugging—examining what gets transferred asynchronously

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Microsoft’s ASP.NET AJAX framework consists of three parts. So far this book has talked about the main features of the Core... more

Microsoft’s ASP.NET AJAX framework consists of three parts. So far this book has talked about the main features of the Core bits and the AJAX Control Toolkit. This chapter provides an overview of the last set of features, collectively part of the ASP.NET AJAX Futures CTP—we will be making updates to the code samples online (www.wrox.com) as the CTPs change. Nothing is guaranteed to be in the Futures CTP, and some bits will be cut out and not put into the next release based on feedback and testing.

The following are the main features of the ASP.NET AJAX CTP as it exists at the time of the ASP.NET AJAX 1.0 release:

• XML-Script

• Data binding

• Drag and drop

• Bridging

• Silverlight with AJAX

Note

One of the goals of this book is to allow a beginner to run the code with as little modification as possible. Because we are unable to know what changes are in store for the features within the ASP.NET AJAX Futures CTP, we decided not to cover these features in the printed book. Instead, we felt it best to provide some simple examples in the online content that goes with this book. To access the online content, go to www.wrox.com and search for “Beginning ASP.NET 2.0 AJAX.”

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