C++ Outlook MailItem replace body and discard on close

Question

I have an addon in Outlook which adds warning to mailbody and links in the email when email is coming from external or untrusted sources. Anyway, when I replace something in body, when email is opened in full view (no reading pane, double click full view of mail item), I hook mailItem close even and I discard changes, everything works well. (mailitem.onclose(olDiscard))

When I do this with reading pane on, when I discard the changes, Outlook still either saves the changes or when user is trying to close Outlook it asks user "Do you want to save changes to ....." and if user clicked on multiple emails during this period, it shows popup question for ALL emails user clicked and we replaced its body.

What's the solution here? What can I do to fix this? I want to make changes to link and to body, but discard them when user clicks away on another email. End goal is not having Outlook to ask user "Do you want to save changes ..." popups. Please advise.

I can't also make changes to inspector, because inspector is read-only.

P.S. plugin is written in C++.

Answer 1

The solution is to avoid modifying the message body if you do not want to keep the changes.

If you want to show a warning to the user, add a task pane to the inspector. Or simply stamp the message with a category - it will be shown in the inspector.

Answer 2

The Outlook object model doesn't provide anything for handling hyperlinks clicks. As a possible workaround you may consider implementing the following functionality:

1. When the item is selected or opened in Outlook you may replace the original URL with your own where you can pass the original URL as an encoded parameter if needed. So, if it is allowed to open the URL you can redirect the request further. Note, you can use the SelectionChange event of the Explorer class which is fired when the user selects a different or additional Microsoft Outlook item programmatically or by interacting with the user interface. This event also occurs when the user (either programmatically or via the user interface) clicks or switches to a different folder that contains items, because Outlook automatically selects the first item in that folder. However, this event does not occur if the folder is a file-system folder or if any folder with a current Web view is displayed. Also you may consider handling the Open event of Outlook items which is fired when an instance of the parent object is being opened in an Inspector. When this event occurs, the Inspector object is initialized but not yet displayed. The Open event differs from the Read event in that Read occurs whenever the user selects the item in a view that supports in-cell editing as well as when the item is being opened in an inspector.

2. Another possible solution is to register a custom URL handler. So, basically, your registered application will be launched instead of a web browser where you can decide whether to launch a web browser and follow the URL or not. See Installing and Registering Protocol Handlers for more information.