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IsolatedStorageFileStream.BeginRead Method

Begins an asynchronous read.

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

[HostProtectionAttribute(SecurityAction.LinkDemand, ExternalThreading = true)]
public override IAsyncResult BeginRead(
	byte[] buffer,
	int offset,
	int numBytes,
	AsyncCallback userCallback,
	Object stateObject


Type: System.Byte[]
The buffer to read data into.
Type: System.Int32
The byte offset in buffer at which to begin reading.
Type: System.Int32
The maximum number of bytes to read.
Type: System.AsyncCallback
The method to call when the asynchronous read operation is completed. This parameter is optional.
Type: System.Object
The status of the asynchronous read.

Return Value

Type: System.IAsyncResult
An IAsyncResult object that represents the asynchronous read, which is possibly still pending. This IAsyncResult must be passed to this stream's EndRead method to determine how many bytes were read. This can be done either by the same code that called BeginRead or in a callback passed to BeginRead.


An asynchronous read was attempted past the end of the file.

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

You must call EndRead with this IAsyncResult to find out how many bytes were read.


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, 1.1, 1.0

.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.