Tales from the Evil Empire : ADO.NET Data Services

Some MIX talks

Bertrand Le Roy — Mon, 23 Mar 2009 04:14:22 GMT

Stephen Walther just published links to the video, slides and sample code for his Ajax talk at MIX09:

http://stephenwalther.com/blog/archive/2009/03/22/mix-slides-code-and-session-recording.aspx

It’s pretty cool to see all the work we put into Ajax this past year or so presented at MIX. This is a really nice presentation, like Stephen’s always are.

Another presentation I had lots of fun watching (not just because the speaker is making an incredible impression of me but also because I’ve been spending a good part of my time lately contributing to the application he’s showing) is Rob Conery’s. Rob is showing an interesting way to develop ASP.NET applications, aimed at ease of use and customization rather than architectural purity. Check it out, let me know what you think…

http://videos.visitmix.com/MIX09/T62F

Microsoft Ajax 4.0 Preview 4 now available

Bertrand Le Roy — Wed, 18 Mar 2009 07:49:00 GMT

The Microsoft Ajax team made the fourth preview of the 4.0 version available on CodePlex. This is an important release because it enables the full client data story, complete with the ability to get changes back to the server automatically.

Here’s a quick recap of some of the available features:

Getting a client representation of data from an ADO.NET and REST data service.
Rendering data on the client using templates.
Declarative instantiation of client components.
Live bindings, enabling changes in the UI and in the data to be automatically propagated.
Command bubbling for codeless wiring of events in template-driven controls.
Data identity and association management for efficient and consistent client-server data exchanges.
Sending changes back to ADO.NET and REST data services.

In a nutshell, it is probably the easiest way to build a data-driven client application. Check this out:

<div id="peopleView" sys:attach="dataview" class="sys-template"
     dataview:dataprovider="{{ $create(Sys.Data.AdoNetDataContext,
                               {serviceUri: 'PeopleIKnow.svc'})}}"
     dataview:fetchoperation="PeopleIKnow"
     dataview:autofetch="true">
    <fieldset>
        <legend>
            <span>{binding FirstName}</span>
            <span>{binding LastName}</span>
        </legend>
        <img code:if="{{ Photo }}"
             sys:src="{{ 'Images/' + Photo }}"
             alt="{{ FirstName + ' ' + LastName }}" />
        <br />
        <input type="text" id="{{ $id('firstName') }}"
               class="editInPlace name"
               value="{binding FirstName}"
               sys:attach="inplace" inplace:cssclass="editing"/>
        <input type="text" id="{{ $id('lastName') }}"
               class="editInPlace name"
               value="{binding LastName}"
               sys:attach="inplace" inplace:cssclass="editing"/>
    </fieldset>
</div>
<br />
<input id="saveButton" type="button" value="Save" />

This creates a DataView that queries the PeopleIKnow.svc ADO.NET data service, and repeats the markup in the div over the data. The legend contains two spans that will respond to live changes to the data ({binding FirstName and {binding LastName}). The image will only be rendered if there is a photo to show (code:if). It builds the image path using a simple JavaScript expression: {{ ‘Images/’ + Photo }}.

The two input tags are augmented by a custom edit in place behavior (sys:attach=”inplace”) and are bound to the FirstName and LastName data columns so that any change to the value of the field will be propagated to everything that depends on the same data: the data itself of course but also the legend of the fieldset (see video below).

The save button is hooked to the following handler:

$addHandler($get("saveButton"), "click", function() {
    $find("peopleView").get_dataProvider().saveChanges();
}, true);

This handler is super-simple as it only has to call saveChanges on the data provider of the DataView. This is enough because any changes made in the input fields have been propagated to the client data model already, which tracked all changes and can build a simple JSON object to send back to the data service. Here is an example of the kind of JSON object that travels back to the server after I’ve changed Simon’s name through the UI:

{
  "__metadata":{
    "uri":"http://127.0.0.1:26402/Asp.Net_Ajax_Preview_4/
           PeopleIKnow.svc/PeopleIKnow(1)",
    "type":"PeopleIKnowModel.PeopleIKnow"
  },
  "ID":1,
  "FirstName":"Simon",
  "LastName":"Calvert",
  "Photo":"simoncal.jpg"
}

Here’s the application running:

<br/><a href="http://video.msn.com/video.aspx?vid=140e8d2a-8d01-49ab-b96f-77e219f93e40" target="_new" title="ASP.NET Ajax 4.0 Preview 4 ">Video: ASP.NET Ajax 4.0 Preview 4 </a>

The source code can be downloaded from here (contains code licensed under MS-PL):
http://weblogs.asp.net/blogs/bleroy/Samples/Asp.Net_Ajax_Preview_4.zip

But wait, there’s more in stock for the next preview… I’ll post more details about some of those features in the following weeks… Stay tuned…

http://aspnet.codeplex.com/Release/ProjectReleases.aspx?ReleaseId=24645

Wally’s introduction to 3.5 SP1

Bertrand Le Roy — Mon, 29 Dec 2008 19:36:18 GMT

Wally McClure, MVP extraordinaire and ASP Insider, just published a short book about the new features in ASP.NET 3.5 SP1. It is a short and to the point read that should get you started in no time. I wouldn’t have shown web service access as the main advantage of jQuery myself (the selector and animation support adds more value for ASP.NET Ajax developers) but that’s a minor thing, and there are plenty of other resources to learn about jQuery. Topics in Wally’s book include:

Ajax History
Script Combining (including ScriptReferenceProfiler)
jQuery
Routing
Entity Framework
Dynamic Data
ADO.NET Data Services

http://www.wrox.com/WileyCDA/WroxTitle/New-Features-in-ASP-NET-3-5-Service-Pack-1.productCd-0470457341.html

Building a data driven application with ASP.NET Ajax 4.0 and ADO.NET Data Services

Bertrand Le Roy — Fri, 07 Nov 2008 00:37:55 GMT

Jim Wang (one of the great QA people on the Ajax team) just started a blog, and his first post is a very detailed walk through building a data-driven application from scratch using ADO.NET Data Services and the new client templates in ASP.NET Ajax 4.0.

http://weblogs.asp.net/jimwang/archive/2008/11/05/working-with-ado-net-data-services-in-ajax.aspx