Developing with WCF RIA Services Quickly and Effectively

1. Developing with WCF RIA Services Quickly and Effectively Nikhil Kothari Software Architect, Microsoft Corporation Blog: http://www.nikhilk.net Twitter:@nikhilk

2. Agenda • Getting started on an application • End-to-end introduction • Going beyond the basics • Implementing MVVM/ViewModel • Designing the application logic • Tips and guidelines along the way • Sneak peek at future possibilities

3. The RIA Services Vision • Simplify n-tier data-driven application development • A higher level framework on top of existing building blocks • LINQ, Data Access Technologies, WCF, Metadata • Provide an application architecture that scales to fit needs of breadth line-of-business applications

4. What would you like to see? • http://www.nikhilk.net/RIA-Services-MIX10.aspx • Pick a real-world scenario; skip the drag/drop • An example of when UI is not mapped one-to-one with a database table • An example of projections across tables • An example where DAL types are not passed to the client • An example of using a stored procedure • When to use [Invoke] vs. Insert/Update/Delete methods? • How to implement the combobox/lookup table scenario? • How to make RIA Services work with MVVM?

5. An End-to-End Introduction to RIA Services Demo

6. BookClub Application • DomainContext • Stateful view + Bindable Data • class BookShelfContext • EntitySet<Book> Books { get } • EntityQuery<Book> GetBooksQuery() • Entities • class Book • Data members + Validation • DomainService • Stateless CRUD + App Logic • class BookShelfService • IQueryable<Book> GetBooks() • void ShareBook(Book) • void UpdateBook(Book) • void UnshareBook (Book) • Validation, authorization, business rules • Data Model • class Book Data Model + Metadata + Shared Code Services Application Presentation Logic App Logic Data Access Layer Network DB var q = Context.GetBooksQuery() Context.Load(q); Context.Books.Add(newBook); Context.SubmitChanges(); DomainService.Query Invoke GetBooks() Compose query, execute, serialize results DomainService.SubmitChanges Authorize, Validate, Execute, Persist Queries and ChangeSets

7. Thinking ViewModel aka MVVM • A pattern for separating application behavior out of the user interface • Motivation • Facilitate designer/developer workflow, and independent design/development activity • Encapsulate state and operations of application • Improve maintainability • Facilitate testability

8. ViewModel + RIA Services Application Presentation XAML, UI Logic View Model App State, Operations, Notifications Data Model Services, Business Rules

9. Sketching the ViewModel SaveBooks() LoadBooks() LoadMoreBooks() ShareBook() Books SelectedBook (two-way) SelectedBook EditBook() UnshareBook()

10. Implementing the ViewModel Pattern with RIA Services Demo

11. The Role of DomainServices • Encapsulate reusable application logic and expose it as a set of CRUD • Meaningful tasks unique to your application • Interesting implementation scenarios • Constraining results • Validation, authorization and business rules • Shaping data • Aggregating data • Caching • Triggering business processes • …

12. Designing DomainServices - Identifying the Tasks GetBooks ShareBook UpdateBook UnshareBook

13. Designing DomainServices -Identifying the Tasks GetLatestBooks GetBooksOfDay SearchBooks RequestBook

14. Designing DomainServices – Presentation Model Types

15. Layering your DomainServices DomainServices + Entities BookShelf Service BookClubService BookInfo Book IQueryable<BookInfo> GetBooks() void ShareBook() void UnshareBook() void UpdateBook() IQueryable<BookInfo> GetBooks() IQueryable<BookInfo> SearchBooks() IQueryable<BookInfo> GetBooksOfDay() void RequestBook(intbookID) ReferenceDataService Category IQueryable<Category> GetCategories() Data Access Layer + DAL Types Amazon BookClubObjectContext Book Request Checkout Category Member

16. Walkthrough of an Interesting DomainService Implementation Demo

17. Recap: Tips and Guidelines • Constrain your queries • Parameters, business rules, result limits • Define specific operations on your domain service that match your application semantics • Use validation to enforce rules, and provide useful user experience • Member, Entity, Operation, Server-only, Async • Use authorization to restrict access to data and operations • Handle errors – any Load/Submit could fail • Separate out reference data to facilitate sharing and optimal loading

18. Recap: Some More Tips • Focus on the tasks that define your application • Customize your DomainServices • Group logically related tasks per DomainService • Create custom entity types designed for use between client and server when appropriate • Expose sufficient and minimum amount of information • Aggregate, re-shape, project on the server • Consider security, band-width and latency

19. Scaling your DomainServices Databases ADO.NET, ORMs (LTS, EF, …) .NET Clients Silverlight, Phone, WPF Standards Clients JavaScript App Logic Lists/Objects Repository (NHibernate, …) Server Rendering HTML, Sitemaps Services REST/SOAP (Azure, …) Services SOAP, XML, JSON, OData Unit Test Code

20. RIA Services + Windows Phone 7 Demo

21. Related Talks • CL08 – Microsoft Silverlight 4 Business Applications • CL50 – Search Engine Optimization for Microsoft Silverlight • FT15 – Accessing Data in a Microsoft Connected Web Application • EX14 - Understanding the Model-View-ViewModel Pattern • RIA Services Meetup at 8pm today in 24001

22. Roadmap and Further Information • Bits • Today: Feature-complete RC build that works with SL4 and VS2010 RC • V1: Ship with SL4 on top of .NET 4/VS2010 • Hosters starting to get on-board (eg. DiscountASP, OrcsWeb) • More Information • http://silverlight.net/riaservices - RIA Services Online • Blogs • http://www.nikhilk.net • http://blogs.msdn.com/brada • http://jeffhandley.com

23. Call to Action • Get a jumpstart on your next Silverlight-based LOB/data-driven app • RIA Services builds on WCF and Silverlight 4 and provides end-to-end solutions • Takes care of services infrastructure, binding infrastructure • Implement well-architected manageable application, and work well for designer/developer workflow • RIA Services is complemented by patterns such as task-centric design approaches and ViewModel

24. Q&A

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