CloudPageBlob.OpenReadAsync Method (AccessCondition, BlobRequestOptions, OperationContext, CancellationToken)

Initiates an asynchronous operation to open a stream for reading from the blob.

Namespace: Microsoft.WindowsAzure.Storage.Blob
Assembly: Microsoft.WindowsAzure.Storage (in Microsoft.WindowsAzure.Storage.dll)


<DoesServiceRequestAttribute> _
Public Function OpenReadAsync ( _
    accessCondition As AccessCondition, _
    options As BlobRequestOptions, _
    operationContext As OperationContext, _
    cancellationToken As CancellationToken _
) As Task(Of Stream)
public Task<Stream> OpenReadAsync (
    AccessCondition accessCondition,
    BlobRequestOptions options,
    OperationContext operationContext,
    CancellationToken cancellationToken
virtual Task<Stream^>^ OpenReadAsync (
    AccessCondition^ accessCondition, 
    BlobRequestOptions^ options, 
    OperationContext^ operationContext, 
    CancellationToken cancellationToken
) sealed


  • accessCondition
    An AccessCondition object that represents the condition that must be met in order for the request to proceed. If null, no condition is used.
  • operationContext
    An OperationContext object that represents the context for the current operation.
  • cancellationToken
    A CancellationToken to observe while waiting for a task to complete.

Return Value

A Task object of type Stream that represents the asynchronous operation.


On the Stream object returned by this method, the EndRead method must be called exactly once for every BeginRead call. Failing to end the read process before beginning another read process can cause unexpected behavior.

Note that this method always makes a call to the FetchAttributesAsync(AccessCondition,BlobRequestOptions,OperationContext,CancellationToken) method under the covers.

Set the StreamMinimumReadSizeInBytes property before calling this method to specify the minimum number of bytes to buffer when reading from the stream. The value must be at least 16 KB.

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.


Development Platforms

Windows Vista, Windows 7 and Windows Server 2008

See Also


CloudPageBlob Class
CloudPageBlob Members
Microsoft.WindowsAzure.Storage.Blob Namespace