Programming ASP.NET AJAX

461 Pages·2008·6.84 MB·English

Programming ASP.NET AJAX
Christian Wenz
Beijing • Cambridge • Farnham • Köln • Paris • Sebastopol • Taipei • Tokyo
Programming ASP.NET AJAX
by Christian Wenz
Copyright © 2007 Christian Wenz. All rights reserved.
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ISBN-10: 0-596-51424-7
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[M]
Table of Contents
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi
Part I. Basics
1. ASP.NET AJAX, Ajax, and ASP.NET. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
ASP.NET AJAX and Ajax 3
ASP.NET AJAX and ASP.NET 5
ASP.NET AJAX Prerequisites and Installation 6
ASP.NET AJAX Structure and Architecture 12
A First ASP.NET AJAX Example: Hello User 14
The ScriptManager Control 19
Summary 21
For Further Reading 21
2. JavaScript . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
The JavaScript Language 24
Object-Oriented Programming (OOP) 34
Accessing Page Elements 38
DOM Methods 42
Summary 43
For Further Reading 43
3. Ajax. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
The XMLHttpRequest Object 45
The XMLDocument Object 55
JSON 61
Summary 64
For Further Reading 64
v
Part II. ASP.NET AJAX Extensions
4. Using ASP.NET AJAX JavaScriptExtensions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
ASP.NET AJAX Shortcuts and Helper Functions 67
Extensions to Existing JavaScript Objects 70
ASP.NET AJAX OOP Features for JavaScript 71
Client Versions of .NET Classes 83
Summary 87
For Further Reading 87
5. Web Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
Error Handling 88
Page Methods 93
Maintaining Session State 95
Exchanging Complex Data with the Server 100
Consuming Web Services with JavaScript 105
Summary 114
For Further Reading 115
6. UpdatePanel: Refreshing Only PartsofaPage . . . . . . . . . . . . . . . . . . . . . . . . 116
Making a Page Region Updatable 116
Summary 131
For Further Reading 132
7. Using the ASP.NET AJAX Profile Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
Preparing the Web Site 133
Accessing Profile Data 135
Accessing Profile Group Data 139
Summary 144
For Further Reading 144
8. Using the ASP.NET AJAX AuthenticationService. . . . . . . . . . . . . . . . . . . . . . . 145
Preparing the Application 145
Login and Logout 148
Summary 154
For Further Reading 154
vi | Table of Contents
9. Localizing and Globalizing Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
Localization 156
Globalization and Internationalization 169
Summary 173
For Further Reading 173
Part III. ASP.NET AJAX Control Toolkit
10. Using the Control Toolkit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
Installing the Control Toolkit 177
Using the Control Toolkit 181
Summary 184
For Further Reading 184
11. Adding Animation to a Web Page . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185
Animation Framework 185
Drag-and-Drop 193
Summary 195
For Further Reading 196
12. Autocompleting User Input, FightingSpam, and More . . . . . . . . . . . . . . . . 197
Creating an Accordion Pane 197
Maintaining the Relative Position of an Element 199
Adding Autocomplete Behavior to a TextBox Control 201
Attaching a Calendar to a Text Field 208
Dynamically Collapsing a Single Panel 210
Displaying a Pop Up Over a Page 211
Fighting Spam in Blogs and in Other Entry Forms 214
Creating a Tabbed Interface 216
Summary 218
For Further Reading 218
13. Writing Custom Controls and Contributing to the Community . . . . . . . . . . 219
Writing Custom ASP.NET AJAX Controls 219
Contributing to the Control Toolkit 228
Summary 237
For Further Reading 237
Table of Contents | vii
Part IV. ASP.NET AJAX Futures
14. Client Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241
Introducing ASP.NET AJAX Client Controls 241
Using ASP.NET AJAX Controls 242
Handling Control Events 259
Summary 263
For Further Reading 263
15. Binding and Validating Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264
Data Binding 264
Data Validation 280
Summary 296
For Further Reading 296
16. Using Behaviors and Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297
Using Behaviors 297
Using Components 310
Summary 313
For Further Reading 313
17. Using Server Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314
Using a ListView Control 314
Creating a Custom Data Source 330
Summary 336
For Further Reading 336
18. Using Remote Web Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337
Using the Google Web Service 338
Using the Amazon Web Service 345
Transforming a Web Service Result with XSLT 350
Using the Yahoo! Web Service (and REST and XPath) 358
Summary 367
For Further Reading 367
19. Using Animations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 368
Using Animations 368
Using an Animation to Create a Fade Effect 370
viii | Table of Contents
Summary 380
For Further Reading 380
20. Fixing Bookmarks and Back/Forward Buttons . . . . . . . . . . . . . . . . . . . . . . . . 381
Fixing with Code 382
Fixing Bookmarks and Back/Forward Buttons with Controls Using
UpdateHistory 384
Fixing Bookmarks and Back/Forward Buttons with Controls Using the
ASP.NET AJAX Futures 388
Summary 395
For Further Reading 395
21. Web Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 396
Using ASP.NET AJAX with ASP.NET Web Parts 396
Summary 401
For Further Reading 401
Part V. Microsoft AJAX Library
22. Using ASP.NET AJAX with OtherServerTechnologies. . . . . . . . . . . . . . . . . . . 405
Using ASP.NET AJAX with PHP 406
Summary 409
For Further Reading 410
Part VI. Appendixes
A. Debugging ASP.NET AJAX Applications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413
B. XMLHttpRequest Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 426
C. DOM Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 428
D. ASP.NET AJAX Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 432
E. ScriptManager, UpdatePanel, UpdateProgress, and Timer
Declarative Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 435
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 439
Table of Contents | ix
Preface
1
The Wikipedia page for Ajax (http://en.wikipedia.org/wiki/Ajax) provides more than
40 meanings for the word, including the names of two characters in Homer’s Iliad
(Ajax the Great and Ajax the Lesser), the name of an Amsterdam soccer team, a
couple of automobiles, a horse, and—my personal favorite—a household cleaner
made by Colgate. However, Ajax is also the term for a collection of technologies
manysaycouldrevolutionizetheWeb.Ifvariousweblogsandonlineandprintcom-
mentaries are to be believed, Ajax is the future of web development, the enabler of
Web 2.0, and probably a cure for fatal diseases, as well.
Many web developers want to provide their users with a far richer client experience
butdon’twanttowriteaWindowsclientapplication(or,forpracticalreasons,can-
not write one). Ajax could be just what they need. It allows web applications to
behave almost like desktop applications, with features such as keyboard shortcuts
and drag-and-drop placement.
ASP.NET “Atlas” was the code name for a new set of technologies from Microsoft
that provide Ajax-like functionality for the ASP.NET developer. It offered many of
thesamebenefitsforAjaxdevelopmentthatASP.NETprovidesforserver-sidedevel-
opment. In autumn of 2006, the final product name was announced: ASP.NET
AJAX. (However, Atlasis much easier to pronounce.)
I resisted writing about Ajax for quite some time. For years, I had used and written
about the technologies that make up Ajax, but the term itself had to be coined in
early2005beforethetechnologyreallytookoff.Inmyopinion,ClemensVasterssaid
it best: “Web 2.0 yadda yadda AJAX yaddayadda Profit!(?)” (see http://vasters.com/
clemensv/PermaLink,guid,d88c1112-d8da-496e-9fd0-8cf03cf55c32.aspx).
The hype reminds me of the buzz that accompanied XML and web services a few
years back: everybody was talking about them, but few had ever read their specs.
Once reality settled in, the hype vanished and actual real-world applications
appeared that made effective use of both technologies.
xi
IamconvincedthatAjaxwillfollowasimilarpathbutwilltravelitmorequickly.A
tour of the Web will prove that there are already loads of useful Ajax applications
available today.
But, back to my reluctance to write a book about Ajax.
I kept saying that Ajax itself could be explained in 20 to 30 pages. Adding some
background information and examples might produce 75 pages, maybe 100. But
how could I fill the rest of the book? Many of the Ajax books currently on the mar-
ket have to go through contortions to reach a reasonable page count.
My thinking about all of this changed when in September 2005 I attended the
Microsoft Professional Developers Conference conference in Los Angeles and saw
Atlas for the first time. Microsoft was announcing a framework that provided Ajax
functionality but added controls and other tools to make development of modern
webapplicationseasier.Nowthiswassomethingtowriteabout,Ithought.Istarted
workingonamanuscriptbasedontheearly,prereleaseversionofAtlas.Ithadtobe
rewritten several times with every new prerelease drop of Atlas I could get my
hands on. The lack of documentation for the preliminary releases required me to
reverse-engineer the inner workings of Atlas. As a result, this book may describe a
few unofficial ways to accomplish things.
ProgrammingAtlaswaspublishedinSeptemberof2006.Asoneofthefirstbookson
the topic, it provided detailed information on the yet still changing framework. At
theendofJanuary2007,ASP.NETAJAXwasreleasedinitsfinal1.0version.Beyond
thenamechange,theinternalchangesweresovastitactuallyrequiredanewedition
of the book as each and every existing application had to be adapted.
This book will teach you how to create professional, dynamic web pages using the
MicrosoftASP.NETAJAXframework.AcertainamountofJavaScriptandASP.NET
knowledge is required. For your convenience, some JavaScript basics are covered at
the beginning of the book.
Iamabigbelieverinthe“show,don’ttell”principle.Therefore,thisbookcontainsa
largenumberofexamplesshowingyouthekeyaspectsoftheASP.NETAJAXframe-
work.Iamalsoafanoffocusingontherelevantfacts.So,Ihavecreatedsmallexam-
ples, each conveying one or two points; I deliberately avoided putting as many facts
as possible into one very long listing. In my experience as an author and trainer,
shorter examples produce better results and make learning easier.
Also, note that the examples are always very generic. This allows you to add them
directlytoyourownprojectsandmodifyandtweakthemtomeetyourneeds.Every
example is self-contained, making it very easy to use and reuse.
xii | Preface
Who This Book Is For
Thisbookwaswrittenfortwogroupsofwebdevelopers:thosewhoareusingASP.NET
and would like to take their applications a step further through the Ajax technology,
and those who are using another technology but are interested in the ASP.NET AJAX
framework.ItisalsosuitableforJavaScriptprogrammerswhowouldliketoavoidsome
oftheheadachescausedbythenecessityofwritingcross-browsercode.Thelanguages
used in this book are C# and JavaScript. If you need background on these languages,
O’Reilly has some solid introductions to both, including Learning C# 2005, by Jesse
Liberty and Brian MacDonald, and Learning JavaScript, by Shelley Powers.
How This Book Is Organized
Chapter1,ASP.NETAJAX,Ajax,andASP.NET,givesabroadoverviewofAjaxand
theASP.NETAJAXframeworkandthencoverstheinstallationofASP.NETAJAX,a
review of its structure, and a first simple example.
Chapter2, JavaScript, is a concise introduction to JavaScript. Although ASP.NET
AJAXdoesitsbesttohidethefunctionaldetailsfromASP.NETprogrammers,acer-
tain knowledge of JavaScript is required to really master ASP.NET AJAX.
Chapter3, Ajax, explains the technologies beyond the hype. You learn what hap-
pens in the background, how Ajax works, and what it really is all about, in fewer
than 20 pages.
Chapter4, Using ASP.NET AJAX JavaScriptExtensions, describes how ASP.NET
AJAX enriches the functionality of client-side JavaScript by adding new OOP-like
features and even reimplementing some classes of the .NET Framework so they can
be used on the client side.
Chapter5,WebServices,dealswithXMLwebservices.EventhoughASP.NETAJAX
focuses on client-based development, it also adds features for server-side web ser-
vices. This includes features for error management and session support.
Chapter6, UpdatePanel: Refreshing Only PartsofaPage, introduces the UpdatePanel
control that makes individual parts of a web page updateable independent from the
rest of the page, without a page refresh. This is one of the most important elements
of ASP.NET AJAX.
Chapter7, Using the ASP.NET AJAX Profile Service, details how ASP.NET AJAX
provides a JavaScript access to the ASP.NET 2.0 Profile API.
Chapter8, Using the ASP.NET AJAX AuthenticationService, explains the JavaScript
hook into the ASP.NET 2.0 Forms Authentication API.
Preface | xiii