If properly configured, the tags in your VTS application can be associated with a custom help file topic that the end user can execute in one of two ways:
• From the shortcut menu's "Help" option;
• From the "Help" button that appears between the "OK" and "Cancel" buttons on the tag's properties folder if the tag has had its Help Search Key property configured with a valid topic ID.
In order to properly associate custom help file topics with the tags in your application, it is necessary to do the following:
1. Save your custom help file in your application directory.
2. Specify the custom help file in your application's Config.ini [SYSTEM] section's "HelpFile" variable (e.g. "HelpFile = MyCustomHelp.hlp" or "HelpFile = MyCustomHelp.chm").
3. In the Help Search Key property (on the ID tab of the tag's properties folder), enter the numeric map number that is associated with the help topic you wish to open for this tag.
(Detailed instructions on associating custom help file topics with the tags in your application can be found in "VTS Developer's Guide: Integrating Custom Help Files Into VTS".)
Internally, the VTS help system is called using a module named, "HelpLaunch". The HelpLaunch module spawns the help file identified in the "HelpFile" variable in the application's Config.ini configuration file. The only parameter passed to the HelpLaunch subroutine is the tag instance (object value). This subroutine displays a warning dialog if the HelpFile program is already open.
The parameter passed to the help file identified in the Config.ini configuration file is the tag's "HelpKey", which is the map ID identifying the topic to display in the help file. If the "HelpFile" variable is not defined, the built-in call to the VTS "Help" function is used, ensuring that only one copy of the help program is open.
The Help command should be built as follows when the HelpFile, Config.ini variable defines a custom help file:
HelpFile HelpKey
The "HelpLaunch" module may be replaced with a custom version if required. The tag's scope is searched first for the "HelpLaunch" module, then the \Code, and the default. This allows a plug-in module to define a help module for each tag type. To hook the help into a Navigator call so that the help file appears when the Help option is selected in the shortcut menu, set "HelpLaunch" as the name of the module to launch with Invalid as the scope of where the module gets launched. It is called from the "ConfigFolder" dialogs, as well as from user code.