Receive Method (Byte[], SocketFlags)

Socket.Receive Method (Byte[], SocketFlags)

 

Receives data from a bound Socket into a receive buffer, using the specified SocketFlags.

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

public int Receive(
	byte[] buffer,
	SocketFlags socketFlags
)

Parameters

buffer
Type: System.Byte[]

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

socketFlags
Type: System.Net.Sockets.SocketFlags

A bitwise combination of the SocketFlags values.

Return Value

Type: System.Int32

The number of bytes received.

Exception Condition
ArgumentNullException

buffer is null.

SocketException

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

ObjectDisposedException

The Socket has been closed.

SecurityException

A caller in the call stack does not have the required permissions.

The Receive method reads data into the buffer parameter and returns the number of bytes successfully read. You can call Receive from both connection-oriented and connectionless sockets.

This overload only requires you to provide a receive buffer and the necessary SocketFlags. The buffer offset defaults to 0, and the size defaults to the length of the byte parameter.

If you are using a connection-oriented protocol, you must either call Connect to establish a remote host connection, or Accept to accept an incoming connection prior to calling Receive. The Receive method will only read data that arrives from the remote host established in the Connect or Accept method. If you are using a connectionless protocol, you can also use the ReceiveFrom method. ReceiveFrom will allow you to receive data arriving from any host.

If no data is available for reading, the Receive method will block until data is available. If you are in non-blocking mode, and there is no data available in the protocol stack buffer, the Receivemethod will complete immediately and throw a SocketException. You can use the Available property to determine if data is available for reading. When Available is non-zero, retry your receive operation.

If you are using a connection-oriented Socket, the Receive method will read as much data as is available up to the size of the buffer. If the remote host shuts down the Socket connection with the Shutdown method, and all available data has been received, the Receive method will complete immediately and return zero bytes.

If you are using a connectionless Socket, Receive will read the first enqueued datagram from the destination address you specify in the Connect method. If the datagram you receive is larger than the size of the buffer parameter, buffer gets filled with the first part of the message, the excess data is lost and a SocketException is thrown.

System_CAPS_noteNote

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.

System_CAPS_noteNote

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

The following code example specifies a data buffer, and SocketFlags for receiving data on a connected Socket.

// Displays sending with a connected socket
// using the overload that takes a buffer and socket flags.
public static int SendReceiveTest2(Socket server)
{
    byte[] msg = Encoding.UTF8.GetBytes("This is a test");
    byte[] bytes = new byte[256];
    try 
    {
        // Blocks until send returns.
        int byteCount = server.Send(msg, SocketFlags.None);
        Console.WriteLine("Sent {0} bytes.", byteCount);

        // Get reply from the server.
        byteCount = server.Receive(bytes, SocketFlags.None);
        if (byteCount > 0)
            Console.WriteLine(Encoding.UTF8.GetString(bytes));
    }
    catch (SocketException e)
    {
        Console.WriteLine("{0} Error code: {1}.", e.Message, e.ErrorCode);
        return (e.ErrorCode);
    }
    return 0;
}

SocketPermission

for accepting connections from the network. Associated enumeration: Accept.

.NET Framework
Available since 1.1
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