Advanced MFC Programming

Chapter 16. Context Sensitive Help
New Commands
Figure 16-3. “Help Topics” property sheet
First, after the standard project is generated, four new commands are added to the application. These
commands are implemented in both the mainframe menu and the tool bar, and their IDs are
ID_HELPTEST_TESTA, ID_HELPTEST_TESTB, ID_HELPTEST_TESTC and ID_HELPTEST_TESTD respectively. In
IDR_MAINFRAME menu, the new commands are Help Test | Test A, Help Test | Test B, Help Test | Test C,
and Help Test | Test D. In the IDR_MAINFRAME tool bar, we also have four buttons corresponding to the four
command IDs. The message handlers of these commands are all blank, because we just want to
demonstrate how to implement context sensitive help for them.
Editing “AfxCore.rtf”
We must add four items to the help file in order to link a command to the help. In order to do this, we
must modify file “AfxCore.rtf”. The rich text format file can be edited by a word processor like Microsoft
Word (WordPad is not powerful enough for this purpose, because it does not support footnote editing).
Within this file, each help item is managed as a footnote. If we want to add a new help item, we just need to
add a new footnote.
To show how to add a footnote to the “.rtf” file, lets assume that we want to add a footnote for
ID_HELPTEST_TESTA command.
Each footnote must be associated with a tag, so that it can be referenced from inside or outside the file.
In Microsoft Word, we can either add number-based tags or user-defined tags. To make the tags
meaningful, usually we define tags by ourselves. The tags can be any string, usually they will have some
relationship with the command IDs implemented in the application. For example, we can use “help_test_A”
as the tag for the footnote that will be used to implement help for the command whose ID is
ID_HELPTEST_TESTA.
To add a new tag within Microsoft Word, first we need to move the cursor to the bottom of the file,
then execute Insert | Break… command. From the popped up dialog box, we need to check the radio
button labeled “Page Break”. If we click “OK” button, a new page will be added to the file (Generally each
footnote needs to use one page, so we need to add page break whenever a new footnote is added). Now
execute Insert | Footnote command, and check the radio button labeled “Footnote” from the popped up
dialog box (in “Insert” section). Then, check radio button labeled “Custom Mark” (in “Numbering”
section) and input a ‘#’ into the edit box beside it (Figure 16-4). Finally, click “OK” button. Now the client
window of Word will split into two panes, the lower of which will show all footnote tags. The caret will be
placed right after the ‘#’ sign waiting for us to type in the footnote tag. We can type “help_test_A”, then
click on the upper pane. Then we can input any help description for command ID_HELPTEST_TESTA.
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