I want our app to show the online help page (so it's always up to date) or even a local page. However, it's likely to be blocked by the Firewall (Zone Alarm).
BTW, I tested this with Zone Alarm. It blocked access to a local .html file as well as to an .asp file on the internet. (I.e., tried to display a page in Internet Explorer and got the Zone Alarm dialog asking if I wanted to give permission to display
Is there a way around this? Perhaps displaying the web page in the Web Browser Control?
If the web browser isn't blocked the firewall then they probably open port 8080 for any app and thus your app shouldn't be blocked.
If the firewall only allowed port 8080 to IE; you would have to punch a hole in the firewall to use a new browser like firefox or chrome.
It's actually very unlikely that web traffic is blocked at the firewall (unless you mean the file type is blocked?). What you may need to do in such a setting, however, is use the same proxy that IE uses, because direct traffic may be blocked.
The simplest way to do that is to use a high level windows API or IE itself, and HTTP download the latest helpfile if there is a new one - these mechanisms should know about any proxy.
Of course, your users may not be using IE, even if most are. So you might need to allow the user to specify the proxy, or be able to auto configure the proxy in the same way that the browser does it.
edit: I see you mean zonealarm is part of the problem. yes, that is tricky as you will have to either get your application 'blessed' centrally by whoever manages zonealarm in the customer organisation, or (if there is no central management) then the user will have to allow the app to communicate. Perhaps you should bite the bullet and have the online help simply be a website, and spawn the preferred browser via 'executing' the URL as suggested in another answer.
To open a web page using the user's preferred browser (with appropriate proxy and authentication settings), use something like ShellExecute with the URL of the document to load. Something like this would do it (where page is the URL to load):
HINSTANCE r = ShellExecute(NULL, "open", page, NULL, NULL, SW_SHOWNORMAL);