<Unknown(DispID=0x0000FC95)> (false) fires when updating "HTMLBody"

Question

I have a C# COM Add-in which inserts custom HTML into the body of the email.

Using OutlookSpy, I see the following events have fired:

PropertyChange (To)
PropertyChange (CC)
PropertyChange (BCC)
PropertyChange (To)
PropertyChange (CC)
PropertyChange (BCC)
PropertyChange (To)
PropertyChange (CC)
PropertyChange (BCC)
PropertyChange (ReceivedTime)
Write (false)
BeforeCheckNames (false)
AfterWrite ()
<Unknown(DispID=0x0000FC95)> (false)
PropertyChange (ConversationTopic)
PropertyChange (ConversationIndex)
PropertyChange (Subject)
PropertyChange (InternetCodepage)
PropertyChange (HTMLBody)
CustomPropertyChange (--- custom data ---)
CustomPropertyChange (--- custom data ---)
CustomPropertyChange (--- custom data ---)
CustomPropertyChange (--- custom data ---)

The code is working fine. I'm wondering what event corresponds to the DISPID 0x0000FC95. I might be able to use it for something in the future.

Answer 1

It is a cancelable version of the AfterWrite event. It is not supported or documented by Microsoft. They introduced it in the OOM, but it never made into the type library. They can take it away at any moment, you are better off not using it.