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GZipStream.BeginRead Method

Begins an asynchronous read operation.

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

[HostProtectionAttribute(SecurityAction.LinkDemand, ExternalThreading = true)]
public override IAsyncResult BeginRead(
	byte[] array,
	int offset,
	int count,
	AsyncCallback asyncCallback,
	Object asyncState
)

Parameters

array
Type: System.Byte[]

The byte array to read the data into.

offset
Type: System.Int32

The byte offset in array at which to begin writing data read from the stream.

count
Type: System.Int32

The maximum number of bytes to read.

asyncCallback
Type: System.AsyncCallback

An optional asynchronous callback, to be called when the read is complete.

asyncState
Type: System.Object

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

Return Value

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

ExceptionCondition
IOException

An asynchronous read past the end of the stream was attempted, or a disk error occurred.

ArgumentException

One or more of the arguments is invalid.

ObjectDisposedException

Methods were called after the stream was closed.

NotSupportedException

The current GZipStream implementation does not support the read operation.

InvalidOperationException

A read operation cannot be performed because the stream is closed.

NoteNote:

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.

Pass the IAsyncResult return value to the EndRead method of the stream to determine how many bytes were read and to release operating system resources used for reading. You can do this either by using the same code that called BeginRead or in a callback passed to BeginRead.

The current position in the stream is updated when the asynchronous read or write is issued, not when the I/O operation completes.

Multiple simultaneous asynchronous requests render the request completion order uncertain.

Use the CanRead property to determine whether the current GZipStream object supports reading.

If a stream is closed or you pass an invalid argument, exceptions are thrown immediately from BeginRead. Errors that occur during an asynchronous read request, such as a disk failure during the I/O request, occur on the thread pool thread and throw exceptions when calling EndRead.

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

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

.NET Framework

Supported in: 3.5, 3.0, 2.0

.NET Compact Framework

Supported in: 3.5

XNA Framework

Supported in: 3.0

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