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DataServiceQuery<TElement>.AddQueryOption Method (String, Object)

 

Creates a new DataServiceQuery<TElement> with the query option set in the URI generated by the returned query.

Namespace:   System.Data.Services.Client
Assembly:  System.Data.Services.Client (in System.Data.Services.Client.dll)

Public Function AddQueryOption (
	name As String,
	value As Object
) As DataServiceQuery(Of TElement)

Parameters

name
Type: System.String

The string value that contains the name of the query string option to add.

value
Type: System.Object

The object that contains the value of the query string option.

Return Value

Type: System.Data.Services.Client.DataServiceQuery<TElement>

A new query that includes the requested query option appended to the URI of the supplied query

The query options are added to the resultant URI using ?name=value&name2=value2… syntax where the name maps directly to the name parameter and the value is obtained by calling ToString on the value parameter. The name starts with $.

Non-WCF Data Services syntax does not start with $. Non-WCF Data Services query options can be added using this method. It is legal to add the same query option twice if the option is not an WCF Data Services query option. If a query option is added that is already present in the underlying URI, an exception is thrown.

The following example shows a DataServiceQuery<TElement> that is used with sequential AddQueryOption method calls to only return orders with a freight cost of more than $30 and to order the results by the ship date in descending order.

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

' Define a query for orders with a Freight value greater than 30
' and that is ordered by the ship date, descending.
Dim selectedOrders As DataServiceQuery(Of Order) = context.Orders _
.AddQueryOption("$filter", "Freight gt 30") _
.AddQueryOption("$orderby", "OrderID desc")

Try
    ' Enumerate over the results of the query.
    For Each order As Order In selectedOrders
        Console.WriteLine("Order ID: {0} - Ship Date: {1} - Freight: {2}", _
                order.OrderID, order.ShippedDate, order.Freight)
    Next
Catch ex As DataServiceQueryException
    Throw New ApplicationException( _
            "An error occurred during query execution.", ex)
End Try

The following example shows how to compose a LINQ query that is equivalent to the previous query that used AddQueryOption.

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

' Define a query for orders with a Freight value greater than 30
' and that is ordered by the ship date, descending.
Dim selectedOrders = From o In context.Orders _
        Where (o.Freight > 30) _
        Order By o.ShippedDate Descending _
        Select o

Try
    ' Enumerate over the results of the query.
    For Each order As Order In selectedOrders
        Console.WriteLine("Order ID: {0} - Ship Date: {1} - Freight: {2}", _
                order.OrderID, order.ShippedDate, order.Freight)
    Next
Catch ex As DataServiceQueryException
    Throw New ApplicationException( _
            "An error occurred during query execution.", ex)
End Try
.NET Framework
Available since 3.5
Silverlight
Available since 2.0
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