System.Net.Sockets.SocketAsyncEventArgs.DoOperationConnect C# (CSharp) Method

        internal unsafe SocketError DoOperationConnect(Socket socket, SafeCloseSocket handle, out int bytesTransferred)
        {
            PrepareIOCPOperation();

            SocketError socketError = SocketError.Success;

            if (!socket.ConnectEx(
                handle,
                _ptrSocketAddressBuffer,
                _socketAddress.Size,
                _ptrSingleBuffer,
                Count,
                out bytesTransferred,
                _ptrNativeOverlapped))
            {
                socketError = SocketPal.GetLastSocketError();
            }

            return socketError;
        }

        public bool ConnectAsync(SocketAsyncEventArgs e)
        {
            bool retval;

            if (s_loggingEnabled)
            {
                Logging.Enter(Logging.Sockets, this, "ConnectAsync", "");
            }

            if (CleanedUp)
            {
                throw new ObjectDisposedException(GetType().FullName);
            }

            if (e == null)
            {
                throw new ArgumentNullException("e");
            }
            if (e._bufferList != null)
            {
                throw new ArgumentException(SR.net_multibuffernotsupported, "BufferList");
            }
            if (e.RemoteEndPoint == null)
            {
                throw new ArgumentNullException("remoteEP");
            }
            if (_isListening)
            {
                throw new InvalidOperationException(SR.net_sockets_mustnotlisten);
            }

            // Check permissions for connect and prepare SocketAddress.
            EndPoint endPointSnapshot = e.RemoteEndPoint;
            DnsEndPoint dnsEP = endPointSnapshot as DnsEndPoint;

            if (dnsEP != null)
            {
                if (s_loggingEnabled)
                {
                    Logging.PrintInfo(Logging.Sockets, "Socket#" + Logging.HashString(this) + "::ConnectAsync " + SR.net_log_socket_connect_dnsendpoint);
                }

                if (dnsEP.AddressFamily != AddressFamily.Unspecified && !CanTryAddressFamily(dnsEP.AddressFamily))
                {
                    throw new NotSupportedException(SR.net_invalidversion);
                }

                MultipleConnectAsync multipleConnectAsync = new SingleSocketMultipleConnectAsync(this, true);

                e.StartOperationCommon(this);
                e.StartOperationWrapperConnect(multipleConnectAsync);

                retval = multipleConnectAsync.StartConnectAsync(e, dnsEP);
            }
            else
            {
                // Throw if remote address family doesn't match socket.
                if (!CanTryAddressFamily(e.RemoteEndPoint.AddressFamily))
                {
                    throw new NotSupportedException(SR.net_invalidversion);
                }

                e._socketAddress = CheckCacheRemote(ref endPointSnapshot, false);

                // Do wildcard bind if socket not bound.
                if (_rightEndPoint == null)
                {
                    if (endPointSnapshot.AddressFamily == AddressFamily.InterNetwork)
                    {
                        InternalBind(new IPEndPoint(IPAddress.Any, 0));
                    }
                    else
                    {
                        InternalBind(new IPEndPoint(IPAddress.IPv6Any, 0));
                    }
                }

                // Save the old RightEndPoint and prep new RightEndPoint.           
                EndPoint oldEndPoint = _rightEndPoint;
                if (_rightEndPoint == null)
                {
                    _rightEndPoint = endPointSnapshot;
                }

                // Prepare for the native call.
                e.StartOperationCommon(this);
                e.StartOperationConnect();

                // Make the native call.
                int bytesTransferred;
                SocketError socketError = SocketError.Success;
                try
                {
                    socketError = e.DoOperationConnect(this, _handle, out bytesTransferred);
                }
                catch (Exception ex)
                {
                    _rightEndPoint = oldEndPoint;

                    // Clear in-use flag on event args object. 
                    e.Complete();
                    throw ex;
                }

                // Handle failure where completion port is not posted.
                if (socketError != SocketError.Success && socketError != SocketError.IOPending)
                {
                    e.FinishOperationSyncFailure(socketError, bytesTransferred, SocketFlags.None);
                    retval = false;
                }
                else
                {
                    retval = true;
                }
            }

            if (s_loggingEnabled)
            {
                Logging.Exit(Logging.Sockets, this, "ConnectAsync", retval);
            }
            return retval;
        }