Stream.WriteAsync Method (Byte[], Int32, Int32)

July 28, 2014

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

Namespace:  System.IO
Assembly:  mscorlib (in mscorlib.dll)

public Task WriteAsync(
	byte[] buffer,
	int offset,
	int count
)

Parameters

buffer
Type: System.Byte []
The buffer to write data from.
offset
Type: System.Int32
The zero-based byte offset in buffer from which to begin copying bytes to the stream.
count
Type: System.Int32
The maximum number of bytes to write.

Return Value

Type: System.Threading.Tasks.Task
A task that represents the asynchronous write operation.

ExceptionCondition
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.

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 Windows 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 reading.

Windows Phone OS

Supported in: 8.1, 8.0

Show:
© 2014 Microsoft