.Net Ria Services for SilverlightIan BlackburnDownload RIA Services and documentation from http://www.microsoft.com/downloads/details.aspx?FamilyID=76bb3a07-3846-4564-b0c3-27972bcaabce&displaylang=enThis presentation is a summary of the ~200 page document from there (plus some examples ;-)

Overviewwww.bbits.co.uk

Where do RIA Services Exist?www.bbits.co.uk

Presentation Technologies and DALs The current preview illustrates the pattern primarily through the end-to-end experience with Silverlight and EF or Linq to Sqlbut RIA Services are designed to work other Presentation and DALS as wellwww.bbits.co.uk

Getting Startedwww.bbits.co.uk

The DomainService ClassThis is the main class for authoring operations Such as CRUD behavioursIt can be generated code in the first instance.You add your custom application logic to this classThe [EnableClientAccess] attribute causes the tools to generate the corresponding client-tier classes when the project is builtwww.bbits.co.uk

The DomainContext ClassA client side DomainContext class is generated for each DomainServiceThis provides basic services such as invocation of operations, accumulation of results, object identity and change tracking www.bbits.co.uk

Sharing Code Between Client and ServerCode that is written in the server side can be reused in the client side. To do thiscreate a new class in the server side with a .shared.cs or .shared.vb suffix Mark the class and methods you want to share with the [Shared] attributeAfter you build the solution, Visual Studio will copy this file to the Silverlight client application:www.bbits.co.uk

Creating Query Methods in the ServiceDefine Query Methods in your Domain ServiceThese must:return a single instance T, or an IEnumerable<T> or IQueryable<T> where T is a valid Entity typetakes 0 or more parameters Optionally be adorned with the QueryAttribute

Using Generated Query Methods in SilverlightWhen a query method is defined in the domain service, the code generator automatically creates A query factory method named [NameOfQueryMethod]QueryThe entity Type of the query method You use it by:createinganEntityQuery instanceApplying LINQ query operators to it as neededPassing the query instance into DomainContext.Load

ExampleNote that the “orderby” is still happening on the server, and the Load is asynchronous

Support Query Operators in SilverlightEntityQuery exposes only a subset of LINQ query operators. These are: Where OrderBy / ThenBySkip / Take

Metadata classesTo add some validation rules that are applied on both tiers, you create a metadata class for the Domain Serviceaffectionately called the “buddy class”This can be generated when you create the domain service by checking the box shownOr you can just add the MetadataType attribute manually to an entity classwww.bbits.co.uk

Using Include on MetaDataYou need to mark the Suppliers metadata with an equivalent Include attribute so the correct code is generated on the client

Adding Validation rules to the Metadata classwww.bbits.co.ukThis is achieved through attributes on the properties of the class on the serverThis causes the generated entity class in the client to have the same validation applied

Modifying DataIf you use the DomainService class wizard to generate DomainService class, then the generated service class has Create/Read/Update/Delete (CRUD) operations already

EntityContainer, EntityList and Change Tracking Entities loaded into a DomainContext are stored and change tracked by its EntityContainerThis is the Entities collection on the context objectAn EntityContainer manages a set of EntityListsthere is a 1:1 mapping between EntityLists and the entity Types exposed by your serviceYou can get a list of entities for a particular type using GetEntityList<T>You can inspect the Entity.EntityState of an entity to determine the state of the entityUnmodified, Modified, New, Deleted

Change Sets (Unit of Work) A change set is a set of one or more entity operations to be processed as a single unit of work and can containEntity Insert/Update/Delete operations Custom domain operationsWhen SubmitChanges is called on the context the changes are all sent to the service all together You can get the current ChangeSet using the GetChanges method of the EntityContainerYou can discard all pending changes, by calling RejectChanges on the context.

Server Side Change Set Processing

Error Handling You can throw validation exceptions in the Domain Service and then handle them in the client SubmitOperation completed event

Other Supported FeaturesConcurrency HandlingConcurrency errors are reported from the DomainService to the clientYou can handle them in the SubmitOperation completed eventYou can also create a Resolve method on your service to deal with resolutionTransactions SupportNo built in support from the client, but you can of course wrap your domain methods in transactionsIdentity Management The Key attribute on entities is used to keep track of local entitiesWhenever an entity is loaded if there is a cached instance locally with the same identity or key value(s) the local instance will be retained, and the newly read instance is discardedYou can change this behaviour with the MergeOption in the context Load method

Custom Methods and Service OperationsUsing Custom MethodsYou can create custom server methods in addition to basic create/update/delete operationsThese also support tracking on entities and deferred execution (e.g. When SubmitChanges is called)Mark them with the [Custom] attributeCall from the context or the entity itself in the clientService Operations More closely related to traditional web serviceUse the [ServiceOperation] attributeDon’t support tracking of deferred execution

Other featuresSilverlight DomainDataSourceUse declarative code to define the interactions between your UI and the data Supports filtering, sorting, grouping, editing...Restrict Access to DomainService Operations You can authenticate using the membership system in asp.netThen configure access against operations roles and usersCode Generated Hook Points Partial methods are supported in the generated code to give extensibility pointsE.g. OnCreated, OnPropertyNameChanged

Other Features.NET RIA Services Class Librariespermits packaging business logic into N-tier class library components rather than the Silverlight client and Web SiteAdo.Net Data ServicesStated goal is to align the two technologies such that Microsoft .NET RIA Services uses the same protocol as ADO.NET Data Services Business Applications TemplatesVS templates that builds on the Silverlight Navigation Application and using .NET RIA Services and provides support for Authentication and User Registration

Questions?

Concurrency Error

Naming ConventionsInsert “Insert”, “Add”, “Create” prefixes Method signature : void InsertX(T entity), where T is an entity Type Update “Update”, “Change”, “Modify” prefixes Method signature : void UpdateX(T current), where T is an entity Type Delete “Delete”, “Remove” prefixes Method signature : void DeleteX(T entity), where T is an entity Type Query Method signature returning a singleton, IEnumerable<T> , IQueryable<T> where T is an entity Type, and taking zero or more parameters Resolve “Resolve” prefix Method signature : boolResolveX(T curr, T original, T store, boolisDelete) where T is an entity type