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GZipStream.BeginWrite Method

Begins an asynchronous write operation.

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

<HostProtectionAttribute(SecurityAction.LinkDemand, ExternalThreading := True)> _
Public Overrides Function BeginWrite ( _
	array As Byte(), _
	offset As Integer, _
	count As Integer, _
	asyncCallback As AsyncCallback, _
	asyncState As Object _
) As IAsyncResult


Type: System.Byte()
The buffer containing data to write to the current stream.
Type: System.Int32
The byte offset in array at which to begin writing.
Type: System.Int32
The maximum number of bytes to write.
Type: System.AsyncCallback
An optional asynchronous callback to be called when the write is complete.
Type: System.Object
A user-provided object that distinguishes this particular asynchronous write request from other requests.

Return Value

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


The underlying stream is Nothing.


The underlying stream is closed.

The BeginWrite method starts an asynchronous write operation to a GZipStream stream object.

You must create a callback method that implements the AsyncCallback delegate and pass its name to the BeginWrite method.


The HostProtectionAttribute attribute applied to this type or member has the following Resources property value: ExternalThreading. The HostProtectionAttribute does not affect desktop applications (which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser). For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes.

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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