We all must be aware of help files and must have prepared them on quite a few occasions. Today we will look at how we can integrate these Help files into our GUI applications. There are two kinds of help files available, one is the old Windows Help Files (.hlp) and other one is the latest compiled HTML help (chm) files. There are two API's for working with these files (one for each type). WinHelp() and HtmlHelp(). These two API's on their own, implement the whole Windows Help system (old as well as new). We will concentrate on HtmlHelp() today. You can look at WinHelp() on your own.

HtmlHelp() function takes four parameters (you can look that up in MSDN). The third parameter is a command parameter which controls the whole behaviour of the help file. There are a lot of commands which can be given in this parameter. For example, if you want to display a certain page from your CHM file, you will use HH_DISPLAY_TOPIC command and specify the topic page in your help file to dispaly. Similarly if you need to show popup help, you will use HH_DISPLAY_TEXT_POPUP and it's associated structure.

There are a lot of commands supported by this API, you can look that up in MSDN. There are commands for popup help, context sensitive help, window management and much more. Also there is a full chapter dedicated to writing help files and itegrating them with your applications. Help authoring and integrating is an integral part of development of any software. So it's important for us to not only be able to author good help, but also integrate it properly.

Many times we totally ignore help files and it's integration with our applications. And many times it's not required because our system projects, rarely have any GUI etc. But whenever it has, make it a point, to write a good help file and integrate it with your applications. It saves a lot of time from user training, preparing user manual etc, plus it gives a very professional look to your applications. HtmlHelp() is a very versatile function, and you should experiment with it a lot to fully understand it's work.

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