Статья
11/18/2011

FileStream.BeginRead Method

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Begins an asynchronous read.

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

Syntax

'Declaration
<SecuritySafeCriticalAttribute> _
Public Overrides Function BeginRead ( _
    array As Byte(), _
    offset As Integer, _
    numBytes As Integer, _
    userCallback As AsyncCallback, _
    stateObject As Object _
) As IAsyncResult

[SecuritySafeCriticalAttribute]
public override IAsyncResult BeginRead(
    byte[] array,
    int offset,
    int numBytes,
    AsyncCallback userCallback,
    Object stateObject
)

Parameters

array
Type: array<System.Byte[]
The buffer to read data into.

offset
Type: System.Int32
The byte offset in array at which to begin reading.

numBytes
Type: System.Int32
The maximum number of bytes to read.

userCallback
Type: System.AsyncCallback
The method to be called when the asynchronous read operation is completed.

stateObject
Type: System.Object
A user-provided object that distinguishes this particular asynchronous read request from other requests.

Return Value

Type: System.IAsyncResult
An IAsyncResult that references the asynchronous read.

Exceptions

Exception	Condition
ArgumentException	The array length minus offset is less than numBytes.
ArgumentNullException	array is nulla null reference (Nothing in Visual Basic).
ArgumentOutOfRangeException	offset or numBytes is negative.
IOException	An asynchronous read was attempted past the end of the file.

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

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