| Constant | Value | Description |
| cdlHelpContext | &H1 | Displays Help for a particular topic |
| cdlHelpQuit | &H2 | Notifies the Help application that the specified Help file is no longer in use |
| cdlHelpIndex | &H3 | Displays the index of the specified Help file |
| cdlHelpContents | &H3 | Displays the contents topic in the current Help file |
| cdlHelpHelpOnHelp | &H4 | Displays Help for using the Help application itself |
| cdlHelpSetIndex | &H5 | Sets the current index for multi-index Help |
| cdlHelpSetContents | &H5 | Designates a specific topic as the contents topic |
| cdlHelpContextPopup | &H8 | Displays a topic identified by a context number |
| cdlHelpForceFile | &H9 | Creates a Help file that displays text in only one font |
| cdlHelpKey | &H101 | Displays Help for a particular keyword |
| cdlHelpCommandHelp | &H102 | Displays Help for a particular command |
| cdlHelpPartialKey | &H105 | Calls the search engine in Windows Help |