服务器端
procedure TForm1.ServerSocket1ClientRead(Sender: TObject;
  Socket: TCustomWinSocket);
begin
  if Socket.ReceiveText[1]='!' then
    Socket.SendText(ListBox1.Items.Text);
end;Client端
procedure TForm1.Button2Click(Sender: TObject);
begin
  ClientSocket1.Socket.SendText('!');
end;procedure TForm1.ClientSocket1Read(Sender: TObject;
  Socket: TCustomWinSocket);
begin
  showmessage(Socket.ReceiveText);
end;