System.Net.Sockets.Socket.EndSend Method

Ends a pending asynchronous send.

Syntax

public int EndSend (IAsyncResult result)

Parameters

result
A IAsyncResult object that holds the state information for the asynchronous operation.

Returns

If successful, the number of bytes sent to the System.Net.Sockets.Socket; otherwise, an invalid System.Net.Sockets.Socket error.

Exceptions

TypeReason
ArgumentNullException asyncResult is null.
ArgumentException asyncResult was not returned by the current instance from a call to the Socket.BeginSend(Byte[], int, int, SocketFlags, AsyncCallback, object) method.
InvalidOperationException Socket.EndSend(IAsyncResult) was previously called for this operation.
System.Net.Sockets.SocketException
Note: For additional information on causes of the SocketException, see the System.Net.Sockets.SocketException class.
ObjectDisposedExceptionThe current instance has been disposed.

Remarks

Socket.EndSend(IAsyncResult) completes the asynchronous send operation started in Socket.BeginSend(Byte[], int, int, SocketFlags, AsyncCallback, object).

Before calling Socket.BeginSend(Byte[], int, int, SocketFlags, AsyncCallback, object), you need to create a callback method that implements the AsyncCallback delegate. This callback method executes in a separate thread and is called by the system after Socket.BeginSend(Byte[], int, int, SocketFlags, AsyncCallback, object) returns. The callback method must accept the IAsyncResult returned by the Socket.BeginSend(Byte[], int, int, SocketFlags, AsyncCallback, object) method as a parameter.

Within the callback method, call the IAsyncResult.AsyncState method of the IAsyncResult parameter to obtain the sending System.Net.Sockets.Socket. After obtaining the System.Net.Sockets.Socket, you can call the Socket.EndSend(IAsyncResult) method to successfully complete the send operation and return the number of bytes sent.

If you are using a connectionless protocol, Socket.EndSend(IAsyncResult) will block until the datagram is sent. If you are using a connection-oriented protocol, Socket.EndSend(IAsyncResult) will block until some of the buffer was sent. If the return value from Socket.EndSend(IAsyncResult) indicates that the buffer was not completely sent, call the erload:System.Net.Sockets.Socket.BeginSend method again, modifying the buffer to hold the unsent data.

There is no guarantee that the data you send will appear on the network immediately. To increase network efficiency, the underlying system may delay transmission until a significant amount of outgoing data is collected. A successful completion of the Socket.BeginSend(Byte[], int, int, SocketFlags, AsyncCallback, object) method means that the underlying system has had room to buffer your data for a network send.

Note:

If you receive a System.Net.Sockets.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.

Note:

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.

Note:

The successful completion of a send does not indicate that the data was successfully delivered. If no buffer space is available within the transport system to hold the data to be transmitted, send will block unless the socket has been placed in nonblocking mode.

Note:

This member outputs trace information when you enable network tracing in your application. For more information, see [<topic://conUsingNetworkTracing>].

Example

For an outline of an asynchronous operation, see the Socket.BeginAccept(AsyncCallback, object) method. For the complete example, which uses the Socket.EndSend(IAsyncResult) method, see the System.Net.Sockets.Socket class overview.

Requirements

Namespace: System.Net.Sockets
Assembly: System (in System.dll)
Assembly Versions: 1.0.5000.0, 2.0.0.0, 4.0.0.0