Query Class

Definition

Namespace:

Microsoft.Azure.Devices.Provisioning.Service

Assembly:

Microsoft.Azure.Devices.Provisioning.Service.dll

Package:

Microsoft.Azure.Devices.Provisioning.Service v1.18.1

The query iterator.

public class Query : IDisposable

type Query = class
    interface IDisposable

Public Class Query
Implements IDisposable

Inheritance

Object

Query

Implements

IDisposable

Remarks

The Query iterator is the result of the query factory for

• IndividualEnrollment
• EnrollmentGroup
• RegistrationStatus

On all cases, the QuerySpecification contains a SQL query that must follow the Query Language for the Device Provisioning Service.

Optionally, an Integer with the page size, can determine the maximum number of the items in the QueryResult returned by the NextAsync(). It must be any positive integer, and if it contains 0, the Device Provisioning Service will ignore it and use a standard page size.

You can use this Object as a standard iterator, just using the HasNext and NextAsync in a while loop, up to the point where the HasNext contains false. But, keep in mind that the QueryResult can contain a empty list, even if the HasNext contained true. For example, image that you have 10 IndividualEnrollment in the Device Provisioning Service and you created new query with the PageSize equals 5. In the first iteration, HasNext will contains true, and the first NextAsync will return a QueryResult with 5 items. After, your code will check the HasNext, which will contains true again. Now, before you get the next page, somebody deletes all the IndividualEnrollment. What happened, when you call the NextAsync, it will return a valid QueryResult, but the Items will contain an empty list.

Besides the Items, the QueryResult contains the ContinuationToken. You can also store a query context (QuerySpecification + ContinuationToken) and restart it in the future, from the point where you stopped. Just recreating the query with the same QuerySpecification and calling the NextAsync(String) passing the stored ContinuationToken.

Properties

ContinuationToken	The token to retrieve the next page.
PageSize	The number of items in the current page.

Methods

Dispose()	Dispose the HTTP resources.
Dispose(Boolean)	Releases the unmanaged resources used by the Component and optionally releases the managed resources.
HasNext()	Getter for has next.
NextAsync()	Return the next page of result for the query.
NextAsync(String)	Return the next page of result for the query using a new continuationToken.