CryptoStream.ReadAsync Method
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
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)
- Source:
- CryptoStream.cs
- Source:
- CryptoStream.cs
- Source:
- CryptoStream.cs
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
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.
The cancellation token was canceled. This exception is stored into the returned task.
Remarks
Important
Starting in .NET 6, this method might not read as many bytes as were requested. For more information, see Partial and zero-byte reads in DeflateStream, GZipStream, and CryptoStream.
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.
This method stores in the task it returns all non-usage exceptions that the method's synchronous counterpart can throw. If an exception is stored into the returned task, that exception will be thrown when the task is awaited. Usage exceptions, such as ArgumentException, are still thrown synchronously. For the stored exceptions, see the exceptions thrown by Read(Byte[], Int32, Int32).
See also
Applies to
ReadAsync(Memory<Byte>, CancellationToken)
- Source:
- CryptoStream.cs
- Source:
- CryptoStream.cs
- Source:
- CryptoStream.cs
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
- cancellationToken
- CancellationToken
The token to monitor for cancellation requests. The default value is None.
Returns
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 the current CryptoStream object does not match the underlying stream. For example, this exception is thrown when using Read with an underlying stream that's write only.
The cancellation token was canceled. This exception is stored into the returned task.
Remarks
Starting in .NET 6, this method might not read as many bytes as were requested. For more information, see Partial and zero-byte reads in DeflateStream, GZipStream, and CryptoStream.
