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# Wx::HelpController

This is a family of classes by which applications invoke a viewer to
provide on-line help. A help controller allows an application to display
help, at the index page or on 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
topics via the application’s menus or buttons.

Typically, an application will create a help controller instance when it
starts, and immediately call load_file to load the help content from a
file. The help viewer will only get run, however, just before the first
call to display something.

Using this class will invoke the most appropriate help viewer on each
different platform, using the native help controller where
possible. This means:

- On desktop Windows, Microsoft HTML Help is used
- On all other platforms, HtmlHelpController is used

These two classes are very similar in functionality and
appearance. Unless you have a strong preference for using the native
help viewer on Windows, it’s recommended that you use
HtmlHelpController directly, rather than using
this class. This has the additional advantage that you only need to
provide help files in one format (.htb) to cover all desktop platforms,
instead of needing to provide a format (.chm) specially for windows. See
HtmlHelpController for more details on the
file formats used.

WxWidgets also provides classes for viewing help on Win CE, but WxRuby
is not currently ported to this platform.

## Derived from

Wx::Object

## See also

HtmlHelpController

## Class Methods

- HelpController.instance
- HelpController.new

## Instance Methods

- HelpController#init
- HelpController#display_block
- HelpController#display_contents
- HelpController#display_context_popup
- HelpController#display_section
- HelpController#display_text_popup
- HelpController#get_frame_parameters
- HelpController#get_parent_window
- HelpController#keyword_search
- HelpController#load_file
- HelpController#on_quit
- HelpController#set_frame_parameters
- HelpController#set_parent_window
- HelpController#set_viewer
- HelpController#quit

## Class Methods

### HtmlHelpController.instance

HelpController.instance()

Returns a new HelpController if one hasn’t already been created, or
returns the previously created one if there is such.

Users typically expect only a single help window to be running for
any particular application, with the help shown and hidden as
required. To avoid showing multiple help windows within a single
application, use this method in preference to
new .

### HelpController.new

HelpController.new()

Constructor.

## Instance Methods

### HelpController#init

init(%(arg-type)String% file)

Initializes the help instance with a help filename. 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
HtmlHelpController, the extensions zip, htb and hhp will be appended
while searching for a suitable file. For WinHelp, the hlp extension is
appended.

### HelpController#display_block

Boolean display_block(%(arg-type)Integer% blockNo)

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

WinHelp: Refers to the context number.

MS HTML Help: Refers to the context number.

External HTML help: the same as for HelpController#display_section.

HtmlHelpController: sectionNo is an identifier as specified in the `.hhc` file. See Help files format.

This function is for backward compatibility only, and applications should use HelpController instead.

### HelpController#display_contents

Boolean display_contents()

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

### HelpController#display_context_popup

Boolean display_context_popup(%(arg-type)Integer% contextId)

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

Returns false if unsuccessful or not implemented.

### HelpController#display_section

Boolean display_section(%(arg-type)String% section)

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

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

Boolean display_section(%(arg-type)Integer% sectionNo)

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

WinHelp, MS HTML Help sectionNo is a context id.

External HTML help: ExtHelpController implements sectionNo as an id in a map file, which is of the form:

0 wx.html ; Index 1 wx34.html#classref ; Class reference 2 wx204.html ; Function reference

HtmlHelpController: sectionNo is an identifier as specified in the `.hhc` file. See Help files format.

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

### HelpController#display_text_popup

Boolean display_text_popup(%(arg-type)String% text, Point pos)

Displays the text in a popup window, if possible.

Returns false if unsuccessful or not implemented.

### HelpController#get_frame_parameters

Frame get_frame_parameters(%(arg-type)Size% size = nil, Point pos = nil, Boolean newFrameEachTime = nil)

HtmlHelpController returns the frame, size and position.

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

#### Parameters

- viewer This defaults to “netscape” for ExtHelpController.
- flags This defaults to HELP_NETSCAPE for ExtHelpController, indicating
  that the viewer is a variant of Netscape Navigator.

### HelpController#get_parent_window

Boolean get_parent_window()

Returns the window to be used as the parent for the help window. This window is used
by CHMHelpController, WinHelpController and HtmlHelpController.

### HelpController#keyword_search

Boolean keyword_search(%(arg-type)String% keyWord, HelpSearchMode mode = HELP_SEARCH_ALL)

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. The optional parameter allows the search the index
(HELP_SEARCH_INDEX) but this currently only supported by the
HtmlHelpController.

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

External HTML help, simple HTML help: If more than one match is found,
a choice of topics is displayed.

HtmlHelpController: see HtmlHelpController#keyword_search.

### HelpController#load_file

Boolean load_file(%(arg-type)String% 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 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.

HtmlHelpController ignores this call.

### HelpController#on_quit

Boolean on_quit()

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

This does not work for all help controllers.

### HelpController#set_frame_parameters

set_frame_parameters(%(arg-type)String% title, Size size, Point pos = DEFAULT_POSITION, Boolean newFrameEachTime = false)

For HtmlHelpController, 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. newFrameEachTime is ignored.

For all other help controllers this function has no effect.

### HelpController#set_parent_window

set_parent_window(%(arg-type)Window% parentWindow)

Sets the window to be used as the parent for the help window. This is used
by CHMHelpController, WinHelpController and HtmlHelpController.

### HelpController#set_viewer

set_viewer(%(arg-type)String% viewer, Integer flags)

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

Some examples of usage:

m_help.SetViewer(“kdehelp”); m_help.SetViewer(“gnome-help-browser”); m_help.SetViewer(“netscape”, HELP_NETSCAPE);

### HelpController#quit

Boolean quit()

If the viewer is running, quits it by disconnecting.

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

[This page automatically generated from the Textile source at 2023-06-09 00:45:37 +0000]