This topic describes new functionality in ADO.NET Data Services that is available as an update to the .NET Framework version 3.5 Service Pack 1. You can download and install the update from the Microsoft Download Center.

ADO.NET Data Services are stateless, but the DataServiceContext is not. State on the client is maintained between interactions in order to support features such as update management. This class, and the DataServiceQuery class that represents a particular HTTP request to a data service, are the two main classes in the client library.

The following example shows how to use the DataServiceContext generated by the Add Service Reference tool to implicitly execute a query against the Northwind data service that returns all customers. The URI of the requested Customers entity set is determined automatically by the context. The query is executed implicitly when the enumeration occurs. The Northwind data service is created when you complete the ADO.NET Data Services quickstart.

' Create the DataServiceContext using the service URI.
Dim context = New NorthwindEntities(svcUri)

' Define a new query for Customers.
Dim query As DataServiceQuery(Of Customers) = context.Customers

Try
    ' Enumerate over the query result, which is executed implicitly.
    For Each customer As Customers In query
        Console.WriteLine("Customer Name: {0}", customer.CompanyName)
    Next
Catch ex As Exception
    Throw New ApplicationException( _
            "An error occurred during query execution.", ex)
End Try

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

.NET Framework

Reference

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