Data Aggregation Using Presentation Model in RIA and Silverlight 4

My earlier post was about the basic CRUD operations on entities with relation .We had discussed about creating simple association and querying as well as Invoking CRUD operation onto them.As i have mentioned there ,here in this article we will have an in-depth look into Presentation Model and its mode of handling related multiple entities.

Introduction , What is Presentation Model ??

Presentation Model deals with data from more than one entities which are related to each other and projecting it as one entity.

Performing CRUD on Relational Data (Multiple table) using RIA in SL4

Introduction

Lots of article demos are available for RIA services but most of them are based on one table without any relational constraint. However, most of the real-time application revolves around data from multiple table and CRUD operations against them.Let’s check one of the queries I received from a reader.

“My issue is. like i have sales Invoice On save button I want to Update Sales master detail table which i can do from ria & after saving i want to update inventory table too . Is there any option i can call update inventory table using this entity.”

Basically the above query seems to be involve RIA service operation with multiple table .Well this post I am going to discuss about Relational/Hierarchical data and CRUD operation against them using RIA.So its time to add some more functionality to the SOI application .

Data Binding in Silverlight with RIA and Entity Framework – Part 3 (Validating Input Data)

Validation is a integral part of software development.In Silverlight validation approach has been changed or you can say evolved from version 2.So this post will highlight the options available for validation with continuation of StatesOfIndia application

Article Series

• Data Binding in Silverlight with RIA and Entity Framework – Part 1 (Displaying Data)
• Data Binding in Silverlight with RIA and Entity Framework – Part 2 (Editing / Updating Data)
• Data Binding in Silverlight with RIA and Entity Framework – Part 3 (Validating Input Data)

Source Code and Demo Link

Hosted Application : Live Sample

Source Code : StatesOfIndia_WithValidation

Data Binding in Silverlight with RIA and Entity Framework – Part 2 (Updating Data)

This is continuation of my earlier post where we discussed How to fetch And display data from database using DomainServiceContext via entity model.Here in this post we will take the StatesOfIndia application further ,where it will accept the state information to be modified as well as accept new state as addition.

Article Series

• Data Binding in Silverlight with RIA and Entity Framework – Part 1 (Displaying Data)
• Data Binding in Silverlight with RIA and Entity Framework – Part 2 (Editing / Updating Data)
• Data Binding in Silverlight with RIA and Entity Framework – Part 3 (Validating Input Data)

Source Code and Demo Link

Hosted Application : Launch StatesOfIndia

Source Code : StatesOfIndia

Data Binding in Silverlight with RIA and EntityFramework – Part 1 (Displaying Data)

Data binding plays a major role for any technology.If you want me to rate the the learning experience of SL then surely Data Binding is going to be  one of the prime destination through journey.Lots of article written and quite a lot of post are available on this specific topic , but with this series of posts tries to introduce you to the concept with minimum content and with a real time sample.

In Data Driven application whole a lot revolve around the data source either in form of Database , XML or any other source ,In my previous posts i think  i was able to give fair bit of introduction on how to create a data model using EnityFramework and RIA services.This post cover up the displaying the data in the UI.

Concept of Binding in Silverlight

To proceed further with this post i guess you may need to have some basic concept of binding .May be writing in detail of this concept will be a repetitive task so I will advise to go through this article from MSDN which is complete in terms of learning resource .

A Real World Scenario

Here i am trying to explain a real application scenario of Master/Detail based data , where the information regarding master will be shown to the detail

Project and Data Model Setup

Create a Silverlight Project with RIA service enabled and add Data Model using Entity Framework .The detailed steps are described in this earlier post.Here the “DataModel_SOI.edmx” Model container shows up the mapped properties to the scalar data fields.The “DomainService_SOI” service class will take care of server side querying

Binding approach

Well the binding approach quite straight forward , we will bind the the state entity collection to the list box while loading of the page.Although the we never intend to show the data as State 1 Stae 2 … object wise format , we will assign a DisplayMember of the entity.The next step is to attach the selected List box item to the Grid layout control which is above the Visual Tree of the controls used for detailing.Once the selected state entity is attached to the Grid Layout the properties can be used a directly to the controls.

Binding to the State List Box

Of course the first step involved is to bind the state entities to the list box and the list should display the state name .The xaml code bellow shows the list box defined with in the Grid layout control in Home page.

1. <ListBox Grid.Row=”1″ HorizontalAlignment=”Left” Margin=”6,2,0,14″
2. Name=”lstStates” Width=”210″
3. FontFamily=”Portable User Interface” FontSize=”13″ FontWeight=”Bold”
4. />

I am going to bind the data to list box with following piece of code while Page Load.

1. private void Page_Loaded(object sender, RoutedEventArgs e)
2. {
3. //Create DataContext Object
4. DomainService_SOI dataContext = new DomainService_SOI();
6. //Use LoadOperation method to Populate the Entity Collection
7. LoadOperation<State> states = dataContext.Load(dataContext.GetStatesQuery());
9. //Bind To List Box
10. lstStates.ItemsSource = states.Entities;
11. lstStates.DisplayMemberPath = “StateName”;//Use StateName as Diplay Name
12. }

Using the Selected List Box Item as DataContext for the Grid Layout

Instead of pointing each individual controls to the selected entity object of list box we are going to bind it to the the parent container of all control.The parent dataContext can be used as a source for other controls.Following piece of code shows how the Grid Layout attached to the selected item.

1. <Grid x:Name=”ContentStackPanel” DataContext=”{Binding SelectedItem,ElementName=lstStates}”>

The point to note here except the List box binding everything we are declaring is in Xaml.The power of declarative programming helps to eradicate the tight coupling of binding to its data source.

Binding to the Detail Controls

The next step will be simple property binding to the DataContext assigned to the parent control.

1. <TextBlock FontWeight=”Bold” Height=”23″ HorizontalAlignment=”Left”
2. Margin=”95,68,0,0″ Name=”tbLanguage” Text=”{Binding Language}“
3. VerticalAlignment=”Top” Grid.Column=”1″ Grid.Row=”1″ />

One point to note here that the Language is property of State Entity which is going to be assigned to the parent grid layout control once the user select an item in list box.I am going to follow the same concept for other controls and my motive of displaying data ready to go.

Lets run the application and check with the data.

Conclusion

Well the data binding is not limited to the only way described above but it is one of the suggested way .This post is limited to displaying of data where in my next post will be continuation of this article where we will use binding concept to track changes , Validation and lots more .

Thanks for your patience , Keep commenting .

Source Code and Links

Download the Source Code for this Project – : StatesOfIndia

Step By Step Guide to WCF RIA enabled SL4 application with Entity Framework

In my last post we discussed about the concepts of WCF Ria services , this post is  continuation of my earlier post.Here we will create a Silverlight 4 based application with WCF RIA services and Entity Framework.Before going through the article make sure you have downloaded the latest SDKs from Microsoft as mention in my last post.

Well we will develop a simple database centric user management system where the admistrator is going to view and edit user detail.For this app we will use remote sqlserver with following tables.

Ingredients for Perfect Web App Recipe , Silverlight 4.0 + WCF RIA Service+ Entity Framework

When Silverlight launched in 2006 , world saw it merely as a flash replacement but with Silverlight 4 things have changed a lot .Now Silverlight far ahead from its adobe competitor at least in terms of technology implementation and rich development environment .RIA enabled Business Apps with Silverlight is not just  a illogical stich of  technology concept but it is a well thought architectural paradigm shift ,In this post i am going to introduce RIA services in .Net framework 4.0 using Silverlight .

What is Silverlight

Needs no introduction , still if you are new then refer this wiki article What is Silverlight.

What is Entity Framework

Well a brief introduction has been published in my earlier posts , Refer ADO.Net Entity Framework

What Is WCF RIA Service

RIA applications give user rich desktop type like UX with client side browser plugin such as Silverlight.It differs from traditional web applications which mostly relies on stateless HTTP Requests to do operations where as RIA employs a State full client and async operation with servers on client demand.

ADO.Net Entity Framework

Well most of our application driven by a relational database and business layer associated with it.The amount of time spent to establish a communication between these two is quite a lot.So here Microsoft introduces a framework for easy data abstraction called Entity Framework (AEF).AEF does wonder with support of LINQ to Entity and here in this post we will have a detailed demonstration.

What Is Entity Framework

It is an abstraction conceptual schema over the logical database schema (Relational database) .It allows us to eradicate the O-R mismatch between RDBMS and the application logic which is common in  data driven applications .(O-R impedance mismatch ,(Details can be found here).