Welcome!

Agile Computing Authors: Yeshim Deniz, Elizabeth White, Stackify Blog, Pat Romanski, Shelly Palmer

Related Topics: Agile Computing, Microsoft Cloud

Agile Computing: Article

A Sneak Peak at ASP.NET AJAX 4.0’s Client-Side Templating

I just want to reiterate how happy I am with the transparency of the ASP.NET team lately

Dave Ward's "Encosia" Blog

Hot on the heels of the recent ASP.NET AJAX roadmap, Bertrand and team have released a limited preview of the new AJAX functionality coming in ASP.NET 4.0.

To see how the new functionality stacks up, I decided to recreate my recent jTemplates example, using only ASP.NET AJAX and its new templating features. Eventually, I settled on using the DataView class, which offers more advanced, repeater-like functionality.

Having successfully completed the exercise, I thought it seemed like something that you might find interesting too. The solution boils down to four easy steps:

  • Creating a page method to return JSON data.
  • Setting up a ScriptManager to coordinate script and page method access.
  • Defining the client-side template that will render the JSON data.
  • Using JavaScript to render the template, using the page method’s return.

A familiar page method

The first order of business is obtaining a data source to render. To keep things simple, let’s reuse the RSS reader from my jQuery “repeater” example:

[WebMethod]
public static IEnumerable GetFeedburnerItems()
{
XDocument feedXML =
XDocument.Load("http://feeds.encosia.com/Encosia");

var feeds =
from feed in feedXML.Descendants("item")
select new
{
Date = DateTime.Parse(feed.Element("pubDate").Value)
.ToShortDateString(),
Title = feed.Element("title").Value,
Link = feed.Element("link").Value,
Description = feed.Element("description").Value
};

return feeds;
}

This page method will return a JSON array representing the latest ten items from my RSS feed. Specifically, their Date, Title, Link, and Description.

Setting up the ScriptManager

The ASP.NET AJAX 4.0 templating features depend on functionality in the ASP.NET AJAX client side framework. We could include MicrosoftAjax.js manually, but since we’re also using a page method, the ScriptManager will serve our needs well:

<asp:ScriptManager runat="server" EnablePageMethods="true">
<Scripts>
<asp:ScriptReference Path="~/MicrosoftAjaxTemplates.js" />
<asp:ScriptReference Path="~/default.js" />
</Scripts>
</asp:ScriptManager>

EnablePageMethods will generate a JavaScript proxy for calling our page method. This is not necessarily the only or most efficient way of calling page methods, but works well enough for our purposes here.

Creating the template

Next, we need to define a template to render the page method’s return upon. The ASP.NET AJAX 4.0 templating engine’s syntax is very straightforward:

<table>
<thead>
<tr>
<th>Date</th>
<th>Title</th>
<th>Excerpt</th>
</tr>
</thead>
<tbody id="RSSItem" class="sys-template">
<tr>
<td>{{ Date }}</td>
<td><a href="{{ Link }}">{{ Title }}</a></td>
<td>{{ Description }}</td>
</tr>
</tbody>
</table>

The bracketed field names correspond to the names of the properties in the anonymous type generated by the page method. It couldn’t be much easier.

You may have noticed the sys-template CSS class applied to the meat of the template. This is a convention for hiding the template until it has been rendered. The class should be defined somewhere as:

.sys-template { display: none; visibility: hidden; }

During the rendering process, the templating engine will automatically attempt to remove the sys-template class, making the final result visible.

Bringing it all together

Now that we’ve got our JSON data source and have defined our template, the final step is simply to connect those dots.

Sys.Application.add_init(AppInit);

// Execute the page method when the page finishes loading.
function AppInit(sender, args) {
PageMethods.GetFeedburnerItems(OnSuccess, OnFailure);
}

function OnSuccess(result) {
// Create an ASP.NET AJAX 4.0 DataView, targeted at our template.
var dv = new Sys.Preview.UI.DataView($get('RSSItem'));

// Pass the DataView our JSON result of RSS items to render.
dv.set_data(result);

// Render the DataView template, using the provided JSON array.
dv.render();
}

// Do not do this in production code!
function OnFailure() { }

The OnSuccess function is where all of the magic happens. When the page method completes its execution, three things happen:

  • A DataView object is created for our template, by passing its containing DomElement: $get(’RSSItem’).
  • The JSON result is assigned to the DataView, using its set_data method.
  • The DataView’s render method is called to generate the end result.

Conclusion and a couple suggestions.

Comparing this implementation to my identical jTemplates example, I must say that I prefer the DataView solution. The syntax is impressively cleaner.

I just want to reiterate how happy I am with the transparency of the ASP.NET team lately. For those of us who aren’t MVPs or ASPInsiders, it’s nice to have a chance to offer constructive feedback and generally not be left in the dark.

In that spirit, I have two suggestions to improve the templating engine.

External templates. I don’t particularly enjoy mingling my template with the rest of the page’s HTML. This is one thing that jTemplates handles very well, with its createTemplateURL method. I would love to see this functionality in the ASP.NET AJAX templating engine and/or the DataView class.

To one-up jTemplates, it would be fantastic if there were a way to pre-load the template. During the second or two that the AJAX call executes would be an excellent time to get the template ready, so that there’s no HTTP delay after the data is ready.

Table issues. Ideally, there should be an automatic convention for hiding the entire table until the template is rendered. Maybe that’s already possible, but I wasn’t able to find a configuration that would do that while repeating only the tbody.

It would make sense if we could assign the entire table a CSS class of sys-template, which would be removed if any of its children were a template being rendered. I usually avoid special cases like this, but I expect that the table scenario will be a prevalent one. It makes sense to optimize for it.

Try it for yourself

Download Source:  dataview-demo.zip (12kb)

 

More Stories By Dave Ward

Dave Ward wrote his first computer program in 1981, using good ‘ol Microsoft Color BASIC and cassette tapes for data storage. Over the years since then, he has had the opportunity to work on projects ranging from simple DOS applications to global telecommunications networks spanning multiple platforms.

Comments (0)

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


@ThingsExpo Stories
Imagine if you will, a retail floor so densely packed with sensors that they can pick up the movements of insects scurrying across a store aisle. Or a component of a piece of factory equipment so well-instrumented that its digital twin provides resolution down to the micrometer.
In his keynote at 18th Cloud Expo, Andrew Keys, Co-Founder of ConsenSys Enterprise, provided an overview of the evolution of the Internet and the Database and the future of their combination – the Blockchain. Andrew Keys is Co-Founder of ConsenSys Enterprise. He comes to ConsenSys Enterprise with capital markets, technology and entrepreneurial experience. Previously, he worked for UBS investment bank in equities analysis. Later, he was responsible for the creation and distribution of life settle...
Product connectivity goes hand and hand these days with increased use of personal data. New IoT devices are becoming more personalized than ever before. In his session at 22nd Cloud Expo | DXWorld Expo, Nicolas Fierro, CEO of MIMIR Blockchain Solutions, will discuss how in order to protect your data and privacy, IoT applications need to embrace Blockchain technology for a new level of product security never before seen - or needed.
BnkToTheFuture.com is the largest online investment platform for investing in FinTech, Bitcoin and Blockchain companies. We believe the future of finance looks very different from the past and we aim to invest and provide trading opportunities for qualifying investors that want to build a portfolio in the sector in compliance with international financial regulations.
Leading companies, from the Global Fortune 500 to the smallest companies, are adopting hybrid cloud as the path to business advantage. Hybrid cloud depends on cloud services and on-premises infrastructure working in unison. Successful implementations require new levels of data mobility, enabled by an automated and seamless flow across on-premises and cloud resources. In his general session at 21st Cloud Expo, Greg Tevis, an IBM Storage Software Technical Strategist and Customer Solution Architec...
Nordstrom is transforming the way that they do business and the cloud is the key to enabling speed and hyper personalized customer experiences. In his session at 21st Cloud Expo, Ken Schow, VP of Engineering at Nordstrom, discussed some of the key learnings and common pitfalls of large enterprises moving to the cloud. This includes strategies around choosing a cloud provider(s), architecture, and lessons learned. In addition, he covered some of the best practices for structured team migration an...
No hype cycles or predictions of a gazillion things here. IoT is here. You get it. You know your business and have great ideas for a business transformation strategy. What comes next? Time to make it happen. In his session at @ThingsExpo, Jay Mason, an Associate Partner of Analytics, IoT & Cybersecurity at M&S Consulting, presented a step-by-step plan to develop your technology implementation strategy. He also discussed the evaluation of communication standards and IoT messaging protocols, data...
Coca-Cola’s Google powered digital signage system lays the groundwork for a more valuable connection between Coke and its customers. Digital signs pair software with high-resolution displays so that a message can be changed instantly based on what the operator wants to communicate or sell. In their Day 3 Keynote at 21st Cloud Expo, Greg Chambers, Global Group Director, Digital Innovation, Coca-Cola, and Vidya Nagarajan, a Senior Product Manager at Google, discussed how from store operations and ...
In his session at 21st Cloud Expo, Raju Shreewastava, founder of Big Data Trunk, provided a fun and simple way to introduce Machine Leaning to anyone and everyone. He solved a machine learning problem and demonstrated an easy way to be able to do machine learning without even coding. Raju Shreewastava is the founder of Big Data Trunk (www.BigDataTrunk.com), a Big Data Training and consulting firm with offices in the United States. He previously led the data warehouse/business intelligence and B...
"IBM is really all in on blockchain. We take a look at sort of the history of blockchain ledger technologies. It started out with bitcoin, Ethereum, and IBM evaluated these particular blockchain technologies and found they were anonymous and permissionless and that many companies were looking for permissioned blockchain," stated René Bostic, Technical VP of the IBM Cloud Unit in North America, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Conventi...
A strange thing is happening along the way to the Internet of Things, namely far too many devices to work with and manage. It has become clear that we'll need much higher efficiency user experiences that can allow us to more easily and scalably work with the thousands of devices that will soon be in each of our lives. Enter the conversational interface revolution, combining bots we can literally talk with, gesture to, and even direct with our thoughts, with embedded artificial intelligence, whic...
When shopping for a new data processing platform for IoT solutions, many development teams want to be able to test-drive options before making a choice. Yet when evaluating an IoT solution, it’s simply not feasible to do so at scale with physical devices. Building a sensor simulator is the next best choice; however, generating a realistic simulation at very high TPS with ease of configurability is a formidable challenge. When dealing with multiple application or transport protocols, you would be...
Smart cities have the potential to change our lives at so many levels for citizens: less pollution, reduced parking obstacles, better health, education and more energy savings. Real-time data streaming and the Internet of Things (IoT) possess the power to turn this vision into a reality. However, most organizations today are building their data infrastructure to focus solely on addressing immediate business needs vs. a platform capable of quickly adapting emerging technologies to address future ...
We are given a desktop platform with Java 8 or Java 9 installed and seek to find a way to deploy high-performance Java applications that use Java 3D and/or Jogl without having to run an installer. We are subject to the constraint that the applications be signed and deployed so that they can be run in a trusted environment (i.e., outside of the sandbox). Further, we seek to do this in a way that does not depend on bundling a JRE with our applications, as this makes downloads and installations rat...
Widespread fragmentation is stalling the growth of the IIoT and making it difficult for partners to work together. The number of software platforms, apps, hardware and connectivity standards is creating paralysis among businesses that are afraid of being locked into a solution. EdgeX Foundry is unifying the community around a common IoT edge framework and an ecosystem of interoperable components.
DX World EXPO, LLC, a Lighthouse Point, Florida-based startup trade show producer and the creator of "DXWorldEXPO® - Digital Transformation Conference & Expo" has announced its executive management team. The team is headed by Levent Selamoglu, who has been named CEO. "Now is the time for a truly global DX event, to bring together the leading minds from the technology world in a conversation about Digital Transformation," he said in making the announcement.
In this strange new world where more and more power is drawn from business technology, companies are effectively straddling two paths on the road to innovation and transformation into digital enterprises. The first path is the heritage trail – with “legacy” technology forming the background. Here, extant technologies are transformed by core IT teams to provide more API-driven approaches. Legacy systems can restrict companies that are transitioning into digital enterprises. To truly become a lead...
Digital Transformation (DX) is not a "one-size-fits all" strategy. Each organization needs to develop its own unique, long-term DX plan. It must do so by realizing that we now live in a data-driven age, and that technologies such as Cloud Computing, Big Data, the IoT, Cognitive Computing, and Blockchain are only tools. In her general session at 21st Cloud Expo, Rebecca Wanta explained how the strategy must focus on DX and include a commitment from top management to create great IT jobs, monitor ...
"Cloud Academy is an enterprise training platform for the cloud, specifically public clouds. We offer guided learning experiences on AWS, Azure, Google Cloud and all the surrounding methodologies and technologies that you need to know and your teams need to know in order to leverage the full benefits of the cloud," explained Alex Brower, VP of Marketing at Cloud Academy, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clar...
The IoT Will Grow: In what might be the most obvious prediction of the decade, the IoT will continue to expand next year, with more and more devices coming online every single day. What isn’t so obvious about this prediction: where that growth will occur. The retail, healthcare, and industrial/supply chain industries will likely see the greatest growth. Forrester Research has predicted the IoT will become “the backbone” of customer value as it continues to grow. It is no surprise that retail is ...