Socket.BeginReceiveMessageFrom Method

Definition

Namespace:

System.Net.Sockets

Assembly:

System.Net.Sockets.dll

Source:

Socket.cs

Begins to asynchronously receive the specified number of bytes of data into the specified location of the data buffer, using the specified SocketFlags, and stores the endpoint and packet information.

public:
 IAsyncResult ^ BeginReceiveMessageFrom(cli::array <System::Byte> ^ buffer, int offset, int size, System::Net::Sockets::SocketFlags socketFlags, System::Net::EndPoint ^ % remoteEP, AsyncCallback ^ callback, System::Object ^ state);

public IAsyncResult BeginReceiveMessageFrom (byte[] buffer, int offset, int size, System.Net.Sockets.SocketFlags socketFlags, ref System.Net.EndPoint remoteEP, AsyncCallback? callback, object? state);

member this.BeginReceiveMessageFrom : byte[] * int * int * System.Net.Sockets.SocketFlags * EndPoint * AsyncCallback * obj -> IAsyncResult

Public Function BeginReceiveMessageFrom (buffer As Byte(), offset As Integer, size As Integer, socketFlags As SocketFlags, ByRef remoteEP As EndPoint, callback As AsyncCallback, state As Object) As IAsyncResult

Parameters

buffer

Byte[]

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

offset

Int32

The zero-based position in the buffer parameter at which to store the data.

size

Int32

The number of bytes to receive.

socketFlags

SocketFlags

A bitwise combination of the SocketFlags values.

remoteEP

EndPoint

A reference to an EndPoint of the same type as the endpoint of the remote host to be updated on synchronous receive.

callback

AsyncCallback

The AsyncCallback delegate.

state

Object

An object that contains state information for this request.

Returns

IAsyncResult

An IAsyncResult that references the asynchronous read.

Exceptions

ArgumentNullException

buffer is null.

-or-

remoteEP is null.

SocketException

.NET Framework and .NET 5 and earlier only: An error occurred when attempting to access the socket.

ArgumentOutOfRangeException

offset is less than 0.

-or-

offset is greater than the length of buffer.

-or-

size is less than 0.

-or-

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

ObjectDisposedException

The Socket has been closed.

Remarks

Important

This is a compatibility API. We don't recommend using the APM (Begin* and End*) methods for new development. Instead, use the Task-based equivalents.

You can pass a callback that implements AsyncCallback to BeginReceiveMessageFrom in order to get notified about the completion of the operation. Note that if the underlying network stack completes the operation synchronously, the callback will be executed inline, during the call to BeginReceiveMessageFrom. In this case, the CompletedSynchronously property on the returned IAsyncResult will be set to true to indicate that the method completed synchronously. Use the AsyncState property of the IAsyncResult to obtain the state object passed to the BeginReceiveMessageFrom method.

The asynchronous BeginReceiveMessageFrom operation must be completed by calling the EndReceiveMessageFrom method. Typically, the method is invoked by the AsyncCallback delegate. EndReceiveMessageFrom will block the calling thread until the operation is completed.

To cancel a pending BeginReceiveMessageFrom, call the Close method.

This method reads data into the buffer parameter, and captures the remote host endpoint from which the data is sent, as well as information about the received packet. For information on how to retrieve this endpoint, refer to EndReceiveMessageFrom. This method is most useful if you intend to asynchronously receive connectionless datagrams from an unknown host or multiple hosts.

Note

If you receive a SocketException, use the SocketException.ErrorCode property to obtain the specific error code.

Note

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

Note

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.