BeginReceive Method (Byte[], Int32, Int32, SocketFlags, SocketError, AsyncCallback, Object)

Socket.BeginReceive Method (Byte[], Int32, Int32, SocketFlags, SocketError, 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)]
public IAsyncResult BeginReceive(
	byte[] buffer,
	int offset,
	int size,
	SocketFlags socketFlags,
	out SocketError errorCode,
	AsyncCallback callback,
	object state


Type: System.Byte[]

An array of type Byte that is the storage location for the received data.

Type: System.Int32

The location in buffer to store the received data.

Type: System.Int32

The number of bytes to receive.

Type: System.Net.Sockets.SocketFlags

A bitwise combination of the SocketFlags values.

Type: System.Net.Sockets.SocketError

A SocketError object that stores the socket error.

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.

Exception Condition

buffer is null.


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


Socket has been closed.


offset is less than 0.


offset is greater than the length of buffer.


size is less than 0.


size is greater than the length of buffer minus the value of the offset parameter.

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 in the .NET Framework.


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.

.NET Framework
Available since 2.0
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