CryptoStream.ReadAsync Method

Definition

Overloads

ReadAsync(Byte[], Int32, Int32, CancellationToken)

Reads a sequence of bytes from the current stream asynchronously, advances the position within the stream by the number of bytes read, and monitors cancellation requests.

ReadAsync(Memory<Byte>, CancellationToken)

Asynchronously reads a sequence of bytes from the current stream, advances the position within the stream by the number of bytes read, and monitors cancellation requests.

ReadAsync(Byte[], Int32, Int32, CancellationToken)

Reads a sequence of bytes from the current stream asynchronously, advances the position within the stream by the number of bytes read, and monitors cancellation requests.

public:
 override System::Threading::Tasks::Task<int> ^ ReadAsync(cli::array <System::Byte> ^ buffer, int offset, int count, System::Threading::CancellationToken cancellationToken);
public override System.Threading.Tasks.Task<int> ReadAsync (byte[] buffer, int offset, int count, System.Threading.CancellationToken cancellationToken);
override this.ReadAsync : byte[] * int * int * System.Threading.CancellationToken -> System.Threading.Tasks.Task<int>
Public Overrides Function ReadAsync (buffer As Byte(), offset As Integer, count As Integer, cancellationToken As CancellationToken) As Task(Of Integer)

Parameters

buffer
Byte[]

The buffer to write the data into.

offset
Int32

The byte offset in buffer at which to begin writing data from the stream.

count
Int32

The maximum number of bytes to read.

cancellationToken
CancellationToken

The token to monitor for cancellation requests. The default value is None.

Returns

Task<Int32>

A task that represents the asynchronous read operation. The value of the task object's TResult parameter contains the total number of bytes read into the buffer. The result can be less than the number of bytes requested if the number of bytes currently available is less than the requested number, or it can be 0 (zero) if the end of the stream has been reached.

Exceptions

buffer is null.

offset or count is negative.

The sum of offset and count is larger than the buffer length.

The stream does not support reading.

The stream has been disposed.

The stream is currently in use by a previous read operation.

Remarks

You must preface your call to ReadAsync with the await (C#) or Await (Visual Basic) operator to suspend execution of the method until the task is complete. For more information, see Asynchronous programming (C#) or Asynchronous programming with Async and Await (Visual Basic).

If the operation is canceled before it completes, the returned task contains the Canceled value for the Status property.

See also

Applies to

ReadAsync(Memory<Byte>, CancellationToken)

Asynchronously reads a sequence of bytes from the current stream, advances the position within the stream by the number of bytes read, and monitors cancellation requests.

public override System.Threading.Tasks.ValueTask<int> ReadAsync (Memory<byte> buffer, System.Threading.CancellationToken cancellationToken = default);
override this.ReadAsync : Memory<byte> * System.Threading.CancellationToken -> System.Threading.Tasks.ValueTask<int>
Public Overrides Function ReadAsync (buffer As Memory(Of Byte), Optional cancellationToken As CancellationToken = Nothing) As ValueTask(Of Integer)

Parameters

buffer
Memory<Byte>

The region of memory to write the data into.

cancellationToken
CancellationToken

The token to monitor for cancellation requests. The default value is None.

Returns

ValueTask<Int32>

A task that represents the asynchronous read operation. The value of its Result property contains the total number of bytes read into the buffer. The result value can be less than the number of bytes allocated in the buffer if that many bytes are not currently available, or it can be 0 (zero) if the end of the stream has been reached.

Exceptions

The CryptoStreamMode associated with current CryptoStream object does not match the underlying stream. For example, this exception is thrown when using Read with an underlying stream that is write only.

Applies to