How can I gracefully shutdown an Indy10 ServerSocket Instance?

Question

I use this snippet to create a new instance of an Indy10 TCPServer:

procedure TPortWindow.AddPort (Item : TListItem);
var
  Socket : TIdTcpServer;
begin
  Socket  := TIdTcpServer.Create(nil);
  try
    Socket.DefaultPort  := strtoint (item.Caption);
    Socket.OnConnect    := MainWindow.OnConnect;
    Socket.OnDisconnect := MainWindow.OnDisconnect;
    Socket.OnExecute    := MainWindow.OnExecute;
    Socket.Active       := TRUE;
  except
    Socket.Free;
    OutputError   ('Error','Port is already in use or blocked by a firewall.' + #13#10 +
                  'Please use another port.');
    Item.Data     := Socket;
    Item.Checked  := FALSE;
  end;
end;

I use this to Delete the instance:

procedure TPortWindow.RemovePort (Item : TListItem);
var
  Socket        : TIdTcpServer;
begin
  if Item.Data = NIL then Exit;
  Socket := TIdTcpServer(Item.Data);
  try
    Socket.Active := FALSE;
  finally
    Socket.Free;
  end;
  Item.Data := NIL;
end;

For some reason the instance does NOT stop listening and all clients stay connected. When I try to make a new instance of the previous Port (after the deletion) it says, that the port is already in use which means it did not stop listening.

How can I properly Shutdown this Instance (and also disconnect all connected clients)?

EDIT:

procedure TMainWindow.OnConnect(AContext: TIdContext);
begin
  ShowMessage ('connected');
end;

procedure TMainWindow.OnDisconnect(AContext: TIdContext);
begin
  ShowMessage ('disconnected');
end;

procedure TMainWindow.OnExecute(AContext: TIdContext);
begin
 // Not defined yet.
end;

Answer 1

Setting the Active property to False is the correct thing to do. It will automatically close the listening port(s) and close any active client connections.

What you do need to watch out for, however, is make sure that your server event handlers are not performing any synchronized operations to the main thread while the main thread is busy deactivating the server, otherwise a deadlock will occur.