Combining index files

Some authors create multiple HTML Help systems and distribute them as a group. This is useful if your project is large and you want to organize it by categories (for example, by modules in your application). With merged .CHM files, the main point of entry is through the Contents and/or Index tabs.

Note: Merging .CHM files is available only with RoboHELP for Microsoft HTML Help.

You can merge index files from the multiple .CHM files into the master .CHM (the file that provides the main point of entry to all other files and topics). You do this by setting up the master project to generate a binary index when it's compiled.

With a binary index, all of the keywords from the secondary .CHM files are merged, alphabetically sorted, and saved in the master project's index file (.HHK). Binary format is ideal because it is highly compressed, takes up less space, and is faster to load.

From the HTML Help viewer, all of the keywords are displayed in alphabetical order. When users select a keyword, the topic that references it opens in the right-hand pane.

Combining indexes with merged HTML Help files is a process that involves the following steps:

  1. Assigning the Binary Index option to the master project (from the Project Settings dialog - Index tab). Index files in the secondary .CHM files do not have to be in binary format.

  2. Adding the secondary .CHM files to the master project (from the Project Settings dialog - Advanced tab).

  3. Compiling the master project.

Notes:

  • Binary indexes are currently only supported with Microsoft HTML Help (not with WebHelp, JavaHelp, or Oracle Help).

  • When you add secondary .CHM files to a master Help project, the Index Designer only displays the keywords used in the master .CHM file when that project is open. The keywords from the secondary .CHM files are only displayed from the Index tab at run time.

  • Binary index files do not support customizations. For example, custom fonts are not used to display keywords from the Index tab, even though you may have applied them to an index in one of the secondary .CHM files.

  • If topics in any of the .CHM files use identical ALink names, all the topics that are assigned to the common ALink name are displayed when users click the ALink buttons.

  • Full-text search is automatically included when you merge index files. However, each individual .CHM file must be compiled to include full-text search for this feature to work.