BufferedStream.WriteAsync Method

Definition

Namespace:

System.IO

Assembly:

System.Runtime.dll

Overloads

WriteAsync(ReadOnlyMemory<Byte>, CancellationToken)	Asynchronously writes a sequence of bytes to the current buffered stream, advances the current position within this buffered stream by the number of bytes written, and monitors cancellation requests.
WriteAsync(Byte[], Int32, Int32, CancellationToken)	Asynchronously writes a sequence of bytes to the current stream, advances the current position within this stream by the number of bytes written, and monitors cancellation requests.

WriteAsync(ReadOnlyMemory<Byte>, CancellationToken)

Source:

BufferedStream.cs

Asynchronously writes a sequence of bytes to the current buffered stream, advances the current position within this buffered stream by the number of bytes written, and monitors cancellation requests.

public override System.Threading.Tasks.ValueTask WriteAsync (ReadOnlyMemory<byte> buffer, System.Threading.CancellationToken cancellationToken = default);

override this.WriteAsync : ReadOnlyMemory<byte> * System.Threading.CancellationToken -> System.Threading.Tasks.ValueTask

Public Overrides Function WriteAsync (buffer As ReadOnlyMemory(Of Byte), Optional cancellationToken As CancellationToken = Nothing) As ValueTask

Parameters

buffer

ReadOnlyMemory<Byte>

The region of memory to write data from.

cancellationToken

CancellationToken

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

Returns

ValueTask

A task that represents the asynchronous write operation.

Exceptions

OperationCanceledException

The cancellation token was canceled. This exception is stored into the returned task.

Remarks

The WriteAsync method enables you to perform resource-intensive I/O operations without blocking the main thread. This performance consideration is particularly important in a Windows 8.x Store app or desktop app where a time-consuming stream operation can block the UI thread and make your app appear as if it is not working. The async methods are used in conjunction with the async and await keywords in Visual Basic and C#.

Use the CanWrite property to determine whether the current instance supports writing.

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

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

Source:

BufferedStream.cs

Asynchronously writes a sequence of bytes to the current stream, advances the current position within this stream by the number of bytes written, and monitors cancellation requests.

public:
 override System::Threading::Tasks::Task ^ WriteAsync(cli::array <System::Byte> ^ buffer, int offset, int count, System::Threading::CancellationToken cancellationToken);

public override System.Threading.Tasks.Task WriteAsync (byte[] buffer, int offset, int count, System.Threading.CancellationToken cancellationToken);

override this.WriteAsync : byte[] * int * int * System.Threading.CancellationToken -> System.Threading.Tasks.Task

Public Overrides Function WriteAsync (buffer As Byte(), offset As Integer, count As Integer, cancellationToken As CancellationToken) As Task

Parameters

buffer

Byte[]

The buffer to write data from.

offset

Int32

The zero-based byte offset in buffer from which to begin copying bytes to the stream.

count

Int32

The maximum number of bytes to write.

cancellationToken

CancellationToken

The token to monitor for cancellation requests.

Returns

Task

A task that represents the asynchronous write operation.

Exceptions

ArgumentNullException

buffer is null.

ArgumentOutOfRangeException

offset or count is negative.

ArgumentException

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

NotSupportedException

The stream does not support writing.

ObjectDisposedException

The stream has been disposed.

InvalidOperationException

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

OperationCanceledException

The cancellation token was canceled. This exception is stored into the returned task.

Remarks

You can create a cancellation token by creating an instance of the CancellationTokenSource class and passing the Token property as the cancellationToken parameter.

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 Write(Byte[], Int32, Int32).