BeginReceive Method (IList(ArraySegment(Byte)), SocketFlags, AsyncCallback, Object)

Socket.BeginReceive Method (IList(ArraySegment(Byte)), SocketFlags, AsyncCallback, Object)

Begins to asynchronously receive data from a connected Socket.

Namespace:  System.Net.Sockets
Assembly:  System (in System.dll)

[<HostProtectionAttribute(SecurityAction.LinkDemand, ExternalThreading = true)>]
member BeginReceive : 
        buffers:IList<ArraySegment<byte>> * 
        socketFlags:SocketFlags * 
        callback:AsyncCallback * 
        state:Object -> IAsyncResult 


Type: System.Collections.Generic.IList(ArraySegment(Byte))
An array of type Byte that is the storage location for the received data.
Type: System.Net.Sockets.SocketFlags
A bitwise combination of the SocketFlags values.
Type: System.AsyncCallback
An AsyncCallback delegate that references the method to invoke when the operation is complete.
Type: System.Object
A user-defined object that contains information about the receive operation. This object is passed to the EndReceive delegate when the operation is complete.

Return Value

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


buffer is a null reference (Nothing in Visual Basic).


An error occurred when attempting to access the socket. See the Remarks section for more information.


Socket has been closed.

The asynchronous BeginReceive operation must be completed by calling the EndReceive method. Typically, the method is invoked by the callback delegate.

This method does not block until the operation is complete. To block until the operation is complete, use one of the Receive method overloads.

To cancel a pending BeginReceive, call the Close method.

For detailed information about using the asynchronous programming model, see Calling Synchronous Methods Asynchronously.


If you receive a SocketException, use the SocketException.ErrorCode property to obtain the specific error code. After you have obtained this code, refer to the Windows Sockets version 2 API error code documentation in the MSDN library for a detailed description of the error.


All I/O initiated by a given thread is canceled when that thread exits. A pending asynchronous operation can fail if the thread exits before the operation completes.


state is an instantiation of a user-defined class.


This member outputs trace information when you enable network tracing in your application. For more information, see Network Tracing.


The execution context (the security context, the impersonated user, and the calling context) is cached for the asynchronous Socket methods. After the first use of a particular context (a specific asynchronous Socket method, a specific Socket instance, and a specific callback), subsequent uses of that context will see a performance improvement.


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.

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