DataServiceQueryContinuation<T> Class

Encapsulates a URI that returns the next page of a paged WCF Data Services query result. 

Inheritance Hierarchy

System.Object
  System.Data.Services.Client.DataServiceQueryContinuation
    System.Data.Services.Client.DataServiceQueryContinuation<T>

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

Syntax

'Declaration
Public NotInheritable Class DataServiceQueryContinuation(Of T) _
    Inherits DataServiceQueryContinuation
'Usage
Dim instance As DataServiceQueryContinuation(Of T)

public sealed class DataServiceQueryContinuation<T> : DataServiceQueryContinuation

generic<typename T>
public ref class DataServiceQueryContinuation sealed : public DataServiceQueryContinuation

[<SealedAttribute>]
type DataServiceQueryContinuation<'T> =  
    class 
        inherit DataServiceQueryContinuation 
    end

JScript does not support generic types and methods.

Type Parameters

• T
  The type of continuation token.

The DataServiceQueryContinuation<T> type exposes the following members.

Properties

	Name	Description
	NextLinkUri	Gets the URI that is used to return the next page of data from a paged query result. (Inherited from DataServiceQueryContinuation.)

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Methods

	Name	Description
	Equals	(Inherited from Object.)
	GetHashCode	(Inherited from Object.)
	GetType	(Inherited from Object.)
	ToString	Returns the next link URI as a string. (Inherited from DataServiceQueryContinuation.)

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Examples

This example uses a do…while loop to load Customers entities from a paged results from the data service.

' Create the DataServiceContext using the service URI.
Dim context = New NorthwindEntities(svcUri)
Dim token As DataServiceQueryContinuation(Of Customer) = Nothing
Dim pageCount = 0

Try
    ' Execute the query for all customers and get the response object.
    Dim response As QueryOperationResponse(Of Customer) = _
        CType(context.Customers.Execute(), QueryOperationResponse(Of Customer))

    ' With a paged response from the service, use a do...while loop 
    ' to enumerate the results before getting the next link.
    Do
        ' Write the page number.
        Console.WriteLine("Page {0}:", pageCount + 1)

        ' If nextLink is not null, then there is a new page to load.
        If token IsNot Nothing Then
            ' Load the new page from the next link URI.
            response = CType(context.Execute(Of Customer)(token),  _
            QueryOperationResponse(Of Customer))
        End If

        ' Enumerate the customers in the response.
        For Each customer As Customer In response
            Console.WriteLine(vbTab & "Customer Name: {0}", customer.CompanyName)
        Next

        ' Get the next link, and continue while there is a next link.
        token = response.GetContinuation()
    Loop While token IsNot Nothing
Catch ex As DataServiceQueryException
    Throw New ApplicationException( _
            "An error occurred during query execution.", ex)
End Try

// Create the DataServiceContext using the service URI.
NorthwindEntities context = new NorthwindEntities(svcUri);
DataServiceQueryContinuation<Customer> token = null;
int pageCount = 0; 

try
{ 
    // Execute the query for all customers and get the response object.
    QueryOperationResponse<Customer> response =
        context.Customers.Execute() as QueryOperationResponse<Customer>;

    // With a paged response from the service, use a do...while loop 
    // to enumerate the results before getting the next link.
    do
    {
        // Write the page number.
        Console.WriteLine("Page {0}:", pageCount++);

        // If nextLink is not null, then there is a new page to load.
        if (token != null)
        {
            // Load the new page from the next link URI.
            response = context.Execute<Customer>(token)
                as QueryOperationResponse<Customer>;
        }

        // Enumerate the customers in the response.
        foreach (Customer customer in response)
        {
            Console.WriteLine("\tCustomer Name: {0}", customer.CompanyName);
        }
    }

    // Get the next link, and continue while there is a next link.
    while ((token = response.GetContinuation()) != null);
}
catch (DataServiceQueryException ex)
{
    throw new ApplicationException(
        "An error occurred during query execution.", ex);
}

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

See Also

Reference

System.Data.Services.Client Namespace

Other Resources

Loading Deferred Content (WCF Data Services)