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BufferedStream.BeginWrite Method

.NET Framework 4.5

Begins an asynchronous write operation. (Consider using WriteAsync instead; see the Remarks section.)

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

public override IAsyncResult BeginWrite(
	byte[] buffer,
	int offset,
	int count,
	AsyncCallback callback,
	Object state
)

Parameters

buffer
Type: System.Byte[]

The buffer containing data to write to the current stream.

offset
Type: System.Int32

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

count
Type: System.Int32

The maximum number of bytes to write.

callback
Type: System.AsyncCallback

The method to be called when the asynchronous write operation is completed.

state
Type: System.Object

A user-provided object that distinguishes this particular asynchronous write request from other requests.

Return Value

Type: System.IAsyncResult
An object that references the asynchronous write which could still be pending.

ExceptionCondition
ArgumentException

buffer length minus offset is less than count.

ArgumentNullException

buffer is null.

ArgumentOutOfRangeException

offset or count is negative.

NotSupportedException

The stream does not support writing.

In the .NET Framework 4 and earlier versions, you have to use methods such as BeginWrite and EndWrite to implement asynchronous file operations. These methods are still available in the .NET Framework 4.5 to support legacy code; however, the new async methods, such as ReadAsync, WriteAsync, and FlushAsync, help you implement asynchronous file operations more easily.

EndWrite must be called exactly once on every IAsyncResult from BeginWrite. EndWrite will block until the I/O operation has completed.

.NET Framework

Supported in: 4.5

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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