\section{\class{wxHelpController}}\label{wxhelpcontroller}

This is a family of classes by which
applications may invoke a help viewer to provide on-line help.

A help controller allows an application to display help, at the contents
or at a particular topic, and shut the help program down on termination.
This avoids proliferation of many instances of the help viewer whenever the
user requests a different topic via the application's menus or buttons.

Typically, an application will create a help controller instance
when it starts, and immediately call {\bf Initialize}\rtfsp
to associate a filename with it. The help viewer will only get run, however,
just before the first call to display something.

Most help controller classes actually derive from wxHelpControllerBase and have
names of the form wxXXXHelpController or wxHelpControllerXXX. An
appropriate class is aliased to the name wxHelpController for each platform, as follows:

\begin{itemize}\itemsep=0pt
\item On Windows, wxWinHelpController is used.
\item On all other platforms, wxHtmlHelpController is used if wxHTML is
compiled into wxWidgets; otherwise wxExtHelpController is used (for invoking an external
browser).
\end{itemize}

The remaining help controller classes need to be named
explicitly by an application that wishes to make use of them.

There are currently the following help controller classes defined:

\begin{itemize}\itemsep=0pt
\item wxWinHelpController, for controlling Windows Help.
\item wxCHMHelpController, for controlling MS HTML Help. To use this, you need to set wxUSE\_MS\_HTML\_HELP
to 1 in setup.h and have htmlhelp.h header from Microsoft's HTML Help kit (you don't need
VC++ specific htmlhelp.lib because wxWidgets loads necessary DLL at runtime and so it
works with all compilers).
\item wxBestHelpController, for controlling MS HTML Help or, if Microsoft's runtime is
not available, \helpref{wxHtmlHelpController}{wxhtmlhelpcontroller}. You need to provide
{\bf both} CHM and HTB versions of the help file. For 32bit Windows only.
\item wxExtHelpController, for controlling external browsers under Unix.
The default browser is Netscape Navigator. The 'help' sample shows its use.
\item \helpref{wxHtmlHelpController}{wxhtmlhelpcontroller}, a sophisticated help controller using \helpref{wxHTML}{wxhtml}, in
a similar style to the Microsoft HTML Help viewer and using some of the same files.
Although it has an API compatible with other help controllers, it has more advanced features, so it is
recommended that you use the specific API for this class instead. Note that if you
use .zip or .htb formats for your books, you
must add this line to your application initialization: {\tt wxFileSystem::AddHandler(new wxZipFSHandler);}
or nothing will be shown in your help window.
\end{itemize}

\wxheading{Derived from}

wxHelpControllerBase\\
\helpref{wxObject}{wxobject}

\wxheading{Include files}

<wx/help.h> (wxWidgets chooses the appropriate help controller class)\\
<wx/helpbase.h> (wxHelpControllerBase class)\\
<wx/helpwin.h> (Windows Help controller)\\
<wx/msw/helpchm.h> (MS HTML Help controller)\\
<wx/generic/helpext.h> (external HTML browser controller)\\
<wx/html/helpctrl.h> (wxHTML based help controller: wxHtmlHelpController)

\wxheading{See also}

\helpref{wxHtmlHelpController}{wxhtmlhelpcontroller}, \helpref{wxHTML}{wxhtml}

\latexignore{\rtfignore{\wxheading{Members}}}

\membersection{wxHelpController::wxHelpController}

\func{}{wxHelpController}{\void}

Constructs a help instance object, but does not invoke the help viewer.

\membersection{wxHelpController::\destruct{wxHelpController}}

\func{}{\destruct{wxHelpController}}{\void}

Destroys the help instance, closing down the viewer if it is running.

\membersection{wxHelpController::Initialize}\label{wxhelpcontrollerinitialize}

\func{virtual void}{Initialize}{\param{const wxString\& }{file}}

\func{virtual void}{Initialize}{\param{const wxString\& }{file}, \param{int}{ server}}

Initializes the help instance with a help filename, and optionally a server socket
number if using wxHelp (now obsolete). Does not invoke the help viewer.
This must be called directly after the help instance object is created and before
any attempts to communicate with the viewer.

You may omit the file extension and a suitable one will be chosen. For
wxHtmlHelpController, the extensions zip, htb and hhp will be appended while searching for
a suitable file. For WinHelp, the hlp extension is appended.

\membersection{wxHelpController::DisplayBlock}\label{wxhelpcontrollerdisplayblock}

\func{virtual bool}{DisplayBlock}{\param{long}{ blockNo}}

If the help viewer is not running, runs it and displays the file at the given block number.

{\it WinHelp:} Refers to the context number.

{\it MS HTML Help:} Refers to the context number.

{\it External HTML help:} the same as for \helpref{wxHelpController::DisplaySection}{wxhelpcontrollerdisplaysection}.

{\it wxHtmlHelpController:} {\it sectionNo} is an identifier as specified in the {\tt .hhc} file. See \helpref{Help files format}{helpformat}.

This function is for backward compatibility only, and applications should use \helpref{wxHelpController}{wxhelpcontrollerdisplaysection} instead.

\membersection{wxHelpController::DisplayContents}\label{wxhelpcontrollerdisplaycontents}

\func{virtual bool}{DisplayContents}{\void}

If the help viewer is not running, runs it and displays the
contents.

\membersection{wxHelpController::DisplayContextPopup}\label{wxhelpcontrollerdisplaycontextpopup}

\func{virtual bool}{DisplayContextPopup}{\param{int }{contextId}}

Displays the section as a popup window using a context id.

Returns FALSE if unsuccessful or not implemented.

\membersection{wxHelpController::DisplaySection}\label{wxhelpcontrollerdisplaysection}

\func{virtual bool}{DisplaySection}{\param{const wxString\&}{ section}}

If the help viewer is not running, runs it and displays the given section.

The interpretation of {\it section} differs between help viewers. For most viewers,
this call is equivalent to KeywordSearch. For MS HTML Help, wxHTML help and external HTML help,
if {\it section} has a .htm
or .html extension, that HTML file will be displayed; otherwise
a keyword search is done.

\func{virtual bool}{DisplaySection}{\param{int}{ sectionNo}}

If the help viewer is not running, runs it and displays the given section.

{\it WinHelp, MS HTML Help} {\it sectionNo} is a context id.

{\it External HTML help:} wxExtHelpController implements {\it sectionNo} as an id in a map file, which is of the form:

\begin{verbatim}
0  wx.html             ; Index
1  wx34.html#classref  ; Class reference
2  wx204.html          ; Function reference
\end{verbatim}

{\it wxHtmlHelpController:} {\it sectionNo} is an identifier as specified in the {\tt .hhc} file. See \helpref{Help files format}{helpformat}.

See also the help sample for notes on how to specify section numbers for various help file formats.

\membersection{wxHelpController::DisplayTextPopup}\label{wxhelpcontrollerdisplaytextpopup}

\func{virtual bool}{DisplayTextPopup}{\param{const wxString\&}{ text}, \param{const wxPoint\& }{pos}}

Displays the text in a popup window, if possible.

Returns FALSE if unsuccessful or not implemented.

\membersection{wxHelpController::GetFrameParameters}\label{wxhelpcontrollergetframeparameters}

\func{virtual wxFrame *}{GetFrameParameters}{\param{const wxSize * }{size = NULL}, \param{const wxPoint * }{pos = NULL},
 \param{bool *}{newFrameEachTime = NULL}}

wxHtmlHelpController returns the frame, size and position.

For all other help controllers, this function does nothing
and just returns NULL.

\wxheading{Parameters}

\docparam{viewer}{This defaults to "netscape" for wxExtHelpController.}

\docparam{flags}{This defaults to wxHELP\_NETSCAPE for wxExtHelpController, indicating
that the viewer is a variant of Netscape Navigator.}

\membersection{wxHelpController::KeywordSearch}\label{wxhelpcontrollerkeywordsearch}

\func{virtual bool}{KeywordSearch}{\param{const wxString\& }{keyWord}}

If the help viewer is not running, runs it, and searches for sections matching the given keyword. If one
match is found, the file is displayed at this section.

{\it WinHelp, MS HTML Help:} If more than one match is found, 
the first topic is displayed.

{\it External HTML help, simple wxHTML help:} If more than one match is found, 
a choice of topics is displayed.

{\it wxHtmlHelpController:} see \helpref{wxHtmlHelpController::KeywordSearch}{wxhtmlhelpcontrollerkeywordsearch}.

\membersection{wxHelpController::LoadFile}\label{wxhelpcontrollerloadfile}

\func{virtual bool}{LoadFile}{\param{const wxString\& }{file = ""}}

If the help viewer is not running, runs it and loads the given file.
If the filename is not supplied or is
empty, the file specified in {\bf Initialize} is used. If the viewer is
already displaying the specified file, it will not be reloaded. This
member function may be used before each display call in case the user
has opened another file.

wxHtmlHelpController ignores this call.

\membersection{wxHelpController::OnQuit}\label{wxhelpcontrolleronquit}

\func{virtual bool}{OnQuit}{\void}

Overridable member called when this application's viewer is quit by the user.

This does not work for all help controllers.

\membersection{wxHelpController::SetFrameParameters}\label{wxhelpcontrollersetframeparameters}

\func{virtual void}{SetFrameParameters}{\param{const wxString \& }{title},
 \param{const wxSize \& }{size}, \param{const wxPoint \& }{pos = wxDefaultPosition},
 \param{bool }{newFrameEachTime = FALSE}}

For wxHtmlHelpController, the title is set (again with \%s indicating the
page title) and also the size and position of the frame if the frame is already
open. {\it newFrameEachTime} is ignored.

For all other help controllers this function has no effect.

\membersection{wxHelpController::SetViewer}\label{wxhelpcontrollersetviewer}

\func{virtual void}{SetViewer}{\param{const wxString\& }{viewer}, \param{long}{ flags}}

Sets detailed viewer information. So far this is only relevant to wxExtHelpController.

Some examples of usage:

\begin{verbatim}
  m_help.SetViewer("kdehelp");
  m_help.SetViewer("gnome-help-browser");
  m_help.SetViewer("netscape", wxHELP_NETSCAPE);
\end{verbatim}

\membersection{wxHelpController::Quit}\label{wxhelpcontrollerquit}

\func{virtual bool}{Quit}{\void}

If the viewer is running, quits it by disconnecting.

For Windows Help, the viewer will only close if no other application is using it.

