QueryClient.CreateAsync<T> Method

Reference

Definition

Namespace:: Microsoft.Azure.Devices

Assembly:: Microsoft.Azure.Devices.dll

Package:: Microsoft.Azure.Devices v2.0.0-preview002

Important

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Execute a query on your IoT hub and get an iterable set of the queried items.

public virtual System.Threading.Tasks.Task<Microsoft.Azure.Devices.QueryResponse<T>> CreateAsync<T> (string query, Microsoft.Azure.Devices.QueryOptions options = default, System.Threading.CancellationToken cancellationToken = default);

abstract member CreateAsync : string * Microsoft.Azure.Devices.QueryOptions * System.Threading.CancellationToken -> System.Threading.Tasks.Task<Microsoft.Azure.Devices.QueryResponse<'T>>
override this.CreateAsync : string * Microsoft.Azure.Devices.QueryOptions * System.Threading.CancellationToken -> System.Threading.Tasks.Task<Microsoft.Azure.Devices.QueryResponse<'T>>

Public Overridable Function CreateAsync(Of T) (query As String, Optional options As QueryOptions = Nothing, Optional cancellationToken As CancellationToken = Nothing) As Task(Of QueryResponse(Of T))

Type Parameters

T

The type to deserialize the set of items into. For example, when running a query like "SELECT * FROM devices", this type should be ClientTwin. When running a query like "SELECT * FROM devices.jobs", this type should be ScheduledJob.

Parameters

query: String

The query. See this document for more details on how to build this query.

options: QueryOptions

The optional parameters to execute the query with.

cancellationToken: CancellationToken

Task cancellation token.

Returns

Task<QueryResponse<T>>

An iterable set of the queried items.

Exceptions

ArgumentNullException

When the provided query is null.

ArgumentException

If the provided query is empty or whitespace.

IotHubServiceException

If IoT hub responded to the request with a non-successful status code. For example, if the provided request was throttled, IotHubServiceException with ThrottlingException is thrown. For a complete list of possible error cases, see IotHubServiceErrorCode.

HttpRequestException

If the HTTP request fails due to an underlying issue such as network connectivity, DNS failure, or server certificate validation.

OperationCanceledException

If the provided cancellation token has requested cancellation.

Examples


  QueryResponse<Twin> queriedTwins = await iotHubServiceClient.Query.CreateAsync<Twin>("SELECT * FROM devices");
  while (await queriedTwins.MoveNextAsync())
  {
      Twin queriedTwin = queriedTwins.Current;
      Console.WriteLine(queriedTwin);
  }


  QueryResponse<ScheduledJob> queriedJobs = await iotHubServiceClient.Query.CreateAsync<ScheduledJob>("SELECT * FROM devices.jobs");
  while (await queriedJobs.MoveNextAsync())
  {
      ScheduledJob queriedJob = queriedJobs.Current;
      Console.WriteLine(queriedJob);
  }

Remarks

The kind of iterable items returned by this query will depend on the query provided.

Applies to

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