Welcome!

Silverlight Authors: Automic Blog, Michael Kopp, AppDynamics Blog, Kaazing Blog, Steven Mandel

Related Topics: Silverlight, Machine Learning

Silverlight: Blog Feed Post

Silverlight 4 + RIA Services: Exposing Data from Entity Framework

How to expose your data from the server side of your application

To continue our series I wanted to look next at how to expose your data from the server side of your application.

The interesting data in your business applications come from a wide variety of data sources.  From a SQL Database, from Oracle DB, from Sql Azure, from Sharepoint, from a mainframe and you have likely already chosen a datamodel such as NHibernate, Linq2Sql, Entity Framework, Stored Proc, a service.   The goal of RIA Service in this release is to make it easy to work with data from any (or many) of the sources in a seamless way from a Silverlight application.  This walk through will use Entity Framework accessing the Sql Express database, but the basic concept applies to any data source.

Add DishView.mdf to BusinessApplication1.Web\App_Data – Of course in a real world example, you’d just have a connection string to an existing database.

Then create an Entity Framework model on top of it.

image_thumb[13]

As you can see, we have a very simple Entity set.. each Restaurant can have any number of Plates.

image_thumb[14]

Next, we need to write some business logic that controls and shapes how to data is seen by the Silverlight client.  To do that, we add a new DomainService.  A DomainService is simply a special kind of WCF service that makes it MUCH easier to query, update, secure and validate your data.    But if you are a WCF expert and know all the ends-and-outs of configuring a WCF service, you can certainly customize this service in exactly the same way to match your needs.   Of course, in the 90% case we hope you will not need to do that.

image_thumb[15]

Next we are given a chance to pre-populate the DomainService.

image_thumb[18]

In this case, we will expose Plate and Restaurant, but only Plate will be updatable.    We will also generate a metadata class for hanging validation attributes on so that you can regenerate the EF model without losing any customizations.    We get a starter DishViewDomainService class.  I have updated it in lines 8-9 with a bit of business logic.   Let’s walk through each line..

  1:     [EnableClientAccess]
  2:     public class DishViewDomainService : LinqToEntitiesDomainService<DishViewEntities>
  3:     {
  4: 
  5:         public IQueryable<Restaurant> GetRestaurants()
  6:         {
  7:             return this.ObjectContext.Restaurants
  8:                 .Where (r=>r.Region != "NC")
  9:                 .OrderBy(r=>r.ID);
 10:         }
 11: 

 

Line 1: This attribute marks the DomainService as accessible over http, without it, the service is only callable from in process. This is useful in the ASP.NET WebForms\Dynamic Data scenario. 
Line 2: We drive this class from the LinqToEntitiesDomainService this is a utility class that provides a few helpers for working with EF.    The real work is done by the DomainService base class, this is the class you derive from for POCO and other custom scenarios.
line 5: Notice we are returning a IQueryable of our DAL Restaurant type.  IQuerable is the interface LINQ is built on.  This enables query capablities from the client so you can do things like sorting, paging, filtering from the client and have it compose with your custom business logic and execute on the data tier..  This means no extra data is sucked into the mid-tier or the client, but you don’t have gunk up your business logic to deal with that. 
Line 8-9: we have some  business logic that weeds out any Restaurant in North Carolina and puts a default ordering on the results. You can of course imagine more interesting business logic.

Read the original blog entry...

More Stories By Brad Abrams

Brad Abrams is currently the Group Program Manager for the UI Framework and Services team at Microsoft which is responsible for delivering the developer platform that spans both client and web based applications, as well as the common services that are available to all applications. Specific technologies owned by this team include ASP.NET, Atlas and Windows Forms. He was a founding member of both the Common Language Runtime, and .NET Framework teams.

Brad has been designing parts of the .NET Framework since 1998 when he started his framework design career building the BCL (Base Class Library) that ships as a core part of the .NET Framework. He was also the lead editor on the Common Language Specification (CLS), the .NET Framework Design Guidelines, the libraries in the ECMA\ISO CLI Standard, and has been deeply involved with the WinFX and Windows Vista efforts from their beginning.

He co-authored Programming in the .NET Environment, and was editor on .NET Framework Standard Library Annotated Reference Vol 1 and Vol 2 and the Framework Design Guidelines.

IoT & Smart Cities Stories
Dion Hinchcliffe is an internationally recognized digital expert, bestselling book author, frequent keynote speaker, analyst, futurist, and transformation expert based in Washington, DC. He is currently Chief Strategy Officer at the industry-leading digital strategy and online community solutions firm, 7Summits.
Digital Transformation is much more than a buzzword. The radical shift to digital mechanisms for almost every process is evident across all industries and verticals. This is often especially true in financial services, where the legacy environment is many times unable to keep up with the rapidly shifting demands of the consumer. The constant pressure to provide complete, omnichannel delivery of customer-facing solutions to meet both regulatory and customer demands is putting enormous pressure on...
IoT is rapidly becoming mainstream as more and more investments are made into the platforms and technology. As this movement continues to expand and gain momentum it creates a massive wall of noise that can be difficult to sift through. Unfortunately, this inevitably makes IoT less approachable for people to get started with and can hamper efforts to integrate this key technology into your own portfolio. There are so many connected products already in place today with many hundreds more on the h...
The standardization of container runtimes and images has sparked the creation of an almost overwhelming number of new open source projects that build on and otherwise work with these specifications. Of course, there's Kubernetes, which orchestrates and manages collections of containers. It was one of the first and best-known examples of projects that make containers truly useful for production use. However, more recently, the container ecosystem has truly exploded. A service mesh like Istio addr...
Digital Transformation: Preparing Cloud & IoT Security for the Age of Artificial Intelligence. As automation and artificial intelligence (AI) power solution development and delivery, many businesses need to build backend cloud capabilities. Well-poised organizations, marketing smart devices with AI and BlockChain capabilities prepare to refine compliance and regulatory capabilities in 2018. Volumes of health, financial, technical and privacy data, along with tightening compliance requirements by...
Charles Araujo is an industry analyst, internationally recognized authority on the Digital Enterprise and author of The Quantum Age of IT: Why Everything You Know About IT is About to Change. As Principal Analyst with Intellyx, he writes, speaks and advises organizations on how to navigate through this time of disruption. He is also the founder of The Institute for Digital Transformation and a sought after keynote speaker. He has been a regular contributor to both InformationWeek and CIO Insight...
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 settlement products to hedge funds and investment banks. After, he co-founded a revenue cycle management company where he learned about Bitcoin and eventually Ethereal. Andrew's role at ConsenSys Enterprise is a mul...
To Really Work for Enterprises, MultiCloud Adoption Requires Far Better and Inclusive Cloud Monitoring and Cost Management … But How? Overwhelmingly, even as enterprises have adopted cloud computing and are expanding to multi-cloud computing, IT leaders remain concerned about how to monitor, manage and control costs across hybrid and multi-cloud deployments. It’s clear that traditional IT monitoring and management approaches, designed after all for on-premises data centers, are falling short in ...
In his general session at 19th Cloud Expo, Manish Dixit, VP of Product and Engineering at Dice, discussed how Dice leverages data insights and tools to help both tech professionals and recruiters better understand how skills relate to each other and which skills are in high demand using interactive visualizations and salary indicator tools to maximize earning potential. Manish Dixit is VP of Product and Engineering at Dice. As the leader of the Product, Engineering and Data Sciences team at D...
Dynatrace is an application performance management software company with products for the information technology departments and digital business owners of medium and large businesses. Building the Future of Monitoring with Artificial Intelligence. Today we can collect lots and lots of performance data. We build beautiful dashboards and even have fancy query languages to access and transform the data. Still performance data is a secret language only a couple of people understand. The more busine...