Data-Driven Services with Silverlight 2

LINQ

Data-driven applications written with Silverlight 2 make extensive use of LINQ and the .NET 3.5 language enhancements in one way or another, as many of the examples in this book will demonstrate. Because of the importance of these features, it is worth taking a look at how they work. C# 3 and Visual Basic (VB) 9 introduced several language enhancements, some of which are integral to writing queries with LINQ. Silverlight 2 applications can consume XML, JSON, objects, entities from LINQ to SQL, and entities from the ADO.NET Entity Framework, to name a few sources.

Silverlight 2 applications often need to gather values from arrays and/or lists of custom entities (e.g., a List<T>). In these cases, LINQ to Objects comes in handy, as it allows you to query any IEnumerable list. Although you can consume and manage XML through a variety of .NET libraries, such as XmlReader, LINQ to XML provides a simpler and often more powerful way to consume XML. This makes it easy for Silverlight applications to consume XML from RSS feeds or REST services and massage the data without resorting to verbose loops. LINQ queries can also join a list of objects and XML, which is very useful when an application is pulling data from multiple sources. This book makes extensive use of LINQ to Objects and LINQ to XML in several chapters in appropriate places where Silverlight applications can take advantage of them.

LINQ to Entities is used heavily in querying the Entity Data Model that the ADO.NET Entity Framework ...