ASP.NET: Taking Ajax to the Next Level
Stephen WaltherSenior Program ManagerMicrosoft Corporation
Introduction
Web Application Experience in 1993
Introduction
Brendan Eich’s Home Page (the inventor of JavaScript)
Introduction
Super Fancy Ajax Application
ASP.NET Server-SidePages are rendered on the server and updated through postbacks
ASP.NET Server-Side AJAX (AJAH)Pages are rendered on the server and updated through AJAX requests for HTML
ASP.NET Client-Side AJAXPages are rendered on the client and updated through Ajax requests for JSON
Different Types of Web Applications
Client-Side Application Model
renders once
Ajax Calls (services)
Less roundtripsLess bandwidthLess work on the web serverMore responsive
Why AJAX Applications Are Good
Two developers: an ASP.NET and JavaScript developer. Ask each developer when a button click event happens…
Why AJAX Applications are Good
Overview: 3 Ways to Build an Application
1. Server-Side ASP.NET
2. Server-Side ASP.NET AJAX
3. Client-Side ASP.NET AJAX
Overview: Features of Client-Side ASP.NET AJAX
1. Declarative Client-Side Controls
2. Command Bubbling
3. Live Bindings
4. Saving and Updating Data
Server-Side ASP.NET with No Ajax
• Controls• Code• Work
Web Server Web Browser
renders
postback
Creating a Master/Detail Page with Server-Side ASP.NET
demo
BenefitsSafe: No Browser Compatibility IssuesPowerful: Use any programming language
DrawbacksResponsiveness: User must wait for a postbackPerformance: All page content must be rendered for each interaction
Server-Side ASP.NET
Server-Side ASP.NET AJAXwith UpdatePanel
• Controls• Code• Work
Web Server Web Browser
renders
sneakypostback
Creating a Master/Detail Page with Server-Side ASP.NET AJAX
demo
Server-Side ASP.NET AJAX
BenefitsSafe: No Browser Compatibility IssuesPowerful: Use any programming languageCompatible: Retrofit existing ASP.NET applications
DrawbacksResponsiveness: User must wait for a postback (no simultaneous Ajax)Performance: (most) page content must be rendered for each interaction
Client-Side ASP.NET AJAX Controls
Web Server Web Browser
renders
sneakypostback
• Code• Work • Controls
Creating a Master/Detail Page with Client-Side AJAX Controls
demo
Client-Side ASP.NET AJAX Controls
Perfection Reached!Benefits
Responsive: Events happen when they happenPerformance: Only necessary content is passed between client and serverClean separation of content and behavior
Data Sources
ASP.NET AJAX is compatible with anything that exposes JSON:
ASMX Web ServicesWCF Web ServicesHTTP HandlersJavaScript arraysASP.NET MVC JSonResultADO.NET Data Services REST Services.NET RIA Services
Why Templates are Good
for (var i=0;i < data.length;i++){ row = "<tr>"; row += "<td>" + data[i].Title + "</td>"; row += "<td>" + data[i].Director +
"</td>"; table += row;}
$get("movieBody").innerHTML = table;
(Evil)
Why Templates are Good
movieView.set_data(data);
<tbody id="movieBody" class="sys-template"><tr> <td>{{ Title }}</td> <td>{{ Director }}</td>
<td>{{ DateReleased.localeFormat("D") }}</td>
</tr></tbody>
(Good)
Rude Objections(impediments to a perfect future)
Browser Back/Forward buttonAccessibilitySearch Engine Optimization (SEO)JavaScript disabled (Mobile Devices)
Creating a Master/Detail Page that supports JavaScript failover
demo
Technology Independent
Client-Side ASP.NET AJAX…
Works with any modern browser including IE, Firefox, Chrome, Safari, and Opera.
Works with any back-end technology that exposes JSON (not dependent on ASP.NET)
Works with HTML pages, no need for ASP.NET.
Creating a Master/Detail Page with Pure HTML
demo
Additional ASP.NET AJAX 4.0 Features
Declarative Client-Side ControlsCommand BubblingLive BindingsSaving and Updating Data
Declarative Controls
XML Namespacesxmlns:sys=“javascript:Sys”xmlns:dataview=“javascript:Sys.UI.DataView”
sys:activateActivates declarative controls
sys:attachAttaches a control to a DOM element
Creating a Master/Detail Page with Declarative Client-Side Controls
demo
Command Bubbling
sys:commandA command name such as select, edit, and so on
sys:commandargumentA command argument such as 78
Sys:commandtargetA control or name of a control that is the target of the command.
onCommandDataView event handler that you can use to handle a custom command
Select Command
DataView PropertiesselectedIndex initialSelectedIndexselectedDataselectedItemClass
Creating a Master/Detail Page with Command Bubbling
demo
Live Bindings
{{ Title }} Used to execute JavaScript in the context of the current data item
{binding Title }WPF style binding syntaxSupports live binding
Live Bindings
One-way, One-time - The data value is updated only the first time that data binding is invoked. {{ CompanyName }}
One-way, Live - If the underlying data item is modified, the rendered data value is updated automatically.<span>{binding CompanyName}</span>
Two-way, Live - If the user changes the data value, the value of the underlying data item is updated. In addition, if the data item is modified from another source, the rendered data value is updated.<input type=“text” value=“{binding CompanyName}” />
Creating a Master/Detail Page with Live Bindings
demo
Data Sources
ASP.NET AJAX is compatible with anything that exposes JSON:
ASMX Web ServicesWCF Web ServicesHTTP HandlersJavaScript arraysASP.NET MVC JSonResultADO.NET Data Services REST Services.NET RIA Services
DataContext Class
Provides read/write access to dataSupports change tracking in the browserSend multiple changes in a single batch to the serverUse AdoNetDataContext class with ADO.NET Data Services
Creating a Master/Detail Page that saves data
demo
Using ADO.NET Data Services
demo
Image Organizer
Conclusion
Embrace the client-side! For better performance and a better user experience, start writing client-side ASP.NET AJAX applications.
CodePlex ASP.NET Previewsaspnet.CodePlex.com
Official ASP.NET Websitewww.ASP.net/ajax
Resources
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