[Lazarus] LHelp or help systems that also work on..

[Graeme Geldenhuys]

On 2016-11-18 11:36, Lars via Lazarus wrote:
> Since I use both Lazarus and Delphi and never just use one or the other,
> is there any help system that works in both delphi and Lazarus?

Yes, Docview and INF help can be used in both cases. I already posted a
full example project for Lazarus LCL applications in the Lazarus Forums.

For Delphi applications you can do the following. Simply set the
HelpContext values for each component or form - as you normally would.
Then implement a global help event handler as shown below. This simply
catches the help request, then launches DocView with the correct
parameters to display the help topic in question.

ps:
  There is a known bug in Delphi 7 where Application.OnHelp is never
  called. Later Delphi versions have fixed this bug. If the application
  is compiled with Delphi 7, then you need to simply catch the WM_HELP
  message in the form, and call AppHelp() explicitly.

========================================
function TForm1.AppHelp(Command: Word; Data: Integer; var CallHelp:
Boolean): Boolean;
const
  cEXE = 'c:\apps\docview.exe myapp.inf -n %d';
var
  SI: TStartupInfo;
  PI: TProcessInformation;
  cmd: string;
begin
  if Command = HELP_CONTEXT then
    CallHelp := False
  else
  begin
    Result := True;
    CallHelp := True;  // don't do anything ourselves.
    Exit;
  end;
  // if we got here, we must display some help.

  cmd := Format(cEXE, [Data]);
  GetStartupInfo(SI);
  // do whatever other setup info you want
  CreateProcess(nil, PChar(cmd), nil, nil, False, 0, nil, nil, SI, PI);
  Result := True;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  Application.HelpFile := 'myapp.inf';
  Application.OnHelp := AppHelp;
end;
==========================================



Regards,
  Graeme

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