How to Link an HTML Help .CHM File with a Delphi Application
The latest versions of the RAD Studio provide support for HTML Help files, which simplifies the task of linking a CHM help file with a Delphi application and providing context-sensitive Help.
Below you will find code examples of the basic actions such as calling a help topic, displaying the Table of Contents or Index tab from the Delphi code.
Define the Full Path to Your CHM Help File
First you need to define the location of your CHM help file by setting the value of the Application.HelpFile property.
Typically, the CHM file is located in the same directory as the application's executable (.EXE) file, so the code below relies on the ExtractFilePath() function.
Application.HelpFile := ExtractFilePath(Application.ExeName) + 'YourCHMFile.chm';
Show a Specific Help Topic by Its Context Number
The code below will open your help file at the topic with Context Number equal to 50:
Application.HelpContext(50);
Show the Table of Contents
If you need to simply display your help file at the default topic, so the user will see the Table of Contents tab open, you can use the call below:
HtmlHelp(0, Application.HelpFile, HH_DISPLAY_TOC, 0);
Show the Index tab
Similarly, you can display your help file and open the Index tab by using this code:
HtmlHelp(0, Application.HelpFile, HH_DISPLAY_INDEX, DWORD(PWideChar('Some keyword here')));
Please note that in this case you can also pass a keyword to find associated topics in the Index tab.
Search for a Keyword
Finally, if you need to search for help topics associated with a keyword directly from your Delphi application, you can use the following line of code:
Application.HelpKeyword('Some keyword here');
Related Links
You can also visit the links below for information on using a CHM file in other development tools.
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