Professional in C# and Visual Basic Part 98. Building on the revolutionary release, adds several key new developer features including AJAX, LINQ, and a new CSS designer in Visual Web Developer 2008. The dramatic reduction in code that developers realized from the more than 50 new server controls in now allows developers the time to make their applications more interactive with AJAX, to work with data in their preferred language with LINQ, and to build visually attractive and consistent standards-based sites with CSS. . | Chapter 19 AJAX asp Button ID Button1 runat server Text Click to initiate async request OnClick Button1_Click div form body html C @ Page Language C script runat server protected void Button1_Click object sender EventArgs e Labell was populated on Label2 was populated on script Now that both of the UpdatePanel controls are set to have an UpdateMode of Conditional when running this page you will see the results presented in Figure 19-15. Figure 19-15 In this case only the right Label control Label1 was updated with the asynchronous request even though the Button1_Click event tries to change the values of both Labell and Label2. The reason for this is that the UpdatePanel2 control had no trigger that was met. Summary AJAX although it is in its infancy is an outstanding technology and will fundamentally change the way Web application development is approached. No longer do you need to completely tear down a page and rebuild it for each and every request. Instead you are able to rebuild the pages slowly in sections as the end user requests them. The line between the thin-client world and the thick-client world just got a lot more opaque. This chapter took a look at the core foundation of AJAX that is available with the default install of Visual Studio 2008. Beyond that there is much more. A big addition is the AJAX Control Toolkit the focus of the next chapter. 928 AJAX Control Toolkit AJAX applications were introduced in the previous chapter. With the install of the .NET Framework and through using Visual Studio 2008 you will find a few controls available that allow you to build applications with AJAX capabilities. This is the framework to take your applications to the next level because there is so much that can be accomplished with it including adding specific AJAX capabilities to your user and custom server controls. Every AJAX enhancement added to your .
