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PipeStream.BeginRead Method

Begins an asynchronous read operation.

Namespace:  System.IO.Pipes
Assembly:  System.Core (in System.Core.dll)

[HostProtectionAttribute(SecurityAction.LinkDemand, ExternalThreading = true)]
public override IAsyncResult BeginRead(
	byte[] buffer,
	int offset,
	int count,
	AsyncCallback callback,
	Object state


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.

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 references the asynchronous read.


buffer is null.


offset is less than 0.


count is less than 0.


count is greater than the number of bytes available in buffer.


The pipe is closed.


The pipe does not support read operations.


The pipe is disconnected, waiting to connect, or the handle has not been set.


The pipe is broken or another I/O error occurred.

Pass the returned IAsyncResult object to the EndRead method to determine how many bytes were read and to release operating system resources used for reading. EndRead must be called once for every call to BeginRead. This can be done either in the same code that called BeginRead or in a callback that is passed to BeginRead.

Use the CanRead property to determine whether the current PipeStream object supports read operations.

If the pipe is closed or an invalid argument is passed to BeginRead, the appropriate exceptions are raised immediately. Errors that occur during an asynchronous read request occur on the thread pool thread that is performing the request. The exceptions are raised when the code calls the EndRead 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: 4.5, 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

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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