'How can an outlook addin detect when an email is deleted

I have created an Outlook addin that handles attachments. When an attachment is added to a mail item I am processing it and adding a user property containing information about the attachment. I have an item send event handler that does the final processing of the attachment just before the mail is sent.

My main issue at this point is that I need to detect when a mail item is deleted so that I can remove the associated resources especially if it was never sent. The before delete event handler seems like the obvious choice for this but doesn't seem to get called.

Can anybody tell me how I can detect when a mail item is deleted? I guess what I probably need to do is detect when it is removed from the "Deleted Items" folder and deleted rather than just being moved to a different folder.

c++sharpoutlook-addin


Solution 1:[1]

The BeforeDelete event of Outlook items is really what you are looking for. 

 Public WithEvents myItem As Outlook.MailItem 

 Public Sub DeleteMail() 
   Const strCancelEvent = "Application-defined or object-defined error" 
   On Error GoTo ErrHandler 
   Set myItem = Application.ActiveInspector.CurrentItem 
   myItem.Delete 
 Exit Sub 

 ErrHandler: 
   MsgBox Err.Description 
   If Err.Description = strCancelEvent Then 
     MsgBox "The event was cancelled." 
   End If 
   'If you want to execute the next instruction 
   Resume Next 
  'Otherwise it will finish here 
 End Sub 

 Private Sub myItem_BeforeDelete(ByVal Item As Object, Cancel As Boolean) 
   'Prompts the user before deleting an item 
   Dim strPrompt As String 
   'Prompt the user for a response 
   strPrompt = "Are you sure you want to delete the item?" 
   If MsgBox(strPrompt, vbYesNo + vbQuestion) = vbNo Then 
     'Don't delete the item 
     Cancel = True 
   End If 
 End Sub

To distinguish between moving to the Deleted Items folder and removing permanently you can add an ItemAdd event to the Deleted Items folder.

Solution 2:[2]

There is no way to easy catch anything related to message deletion. BeforeDelete does not reliably work, plus an item can get deleted when your code is not running (e.g. when a user deletes it from another computer / phone /etc.).

Also keep in mind that all MAPI events are asynchronous, so by the time you get an event, the item is already gone. On the MAPI level, the folder contents table raises TABLE_ROW_DELETED notification, but since the message is already gone, you only get the value of the PR_INSTANCE_KEY property. It can only be useful if you already know PR_INSTANCE_KEY of the particular message or if you have a list of PR_INSTANCE_KEY for all messages in the folder. You can see the event fire in OutlookSpy (I am its author - click IMAPIFolder button, go to the GetContentsTable tab, look at the log at the bottom of the window). If MAPI (C++ or Delphi) is not an option, Redemption (I am also its author) exposes the RDOItems.ItemRemove event, which passes PR_INSTANCE_KEY as the parameter.

Another option under Exchange Server is the Incremental Change Synchronization API. Again, it is pure MAPI and requires C++ or Delphi. Redemption exposes it through the RDOFolderSynchronizer object.

The only generic option is to periodically scan the messages in the folder and check them against your own list to see if any items are missing. This can be a performance bottleneck, even if you optimize its by using the Outlook.Table object to retrieve properties from multiple items in a single call.

Sources

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Source: Stack Overflow

Solution Source
Solution 1 Eugene Astafiev
Solution 2

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