VSTO: Iterating through Outlook inbox raises error when non-mail items appears

Question

I have some code in Visual Studio (VSTO + VB.Net) that shall iterate through all items in my Outlook Inbox. The code works fine until there are other items in my Inbox, such as appointments etc.

The code below is simplified and iterates through all items in a sorted list. The problem occurs when FolderItem (of type MailItem) is assigned with an item that is of other types, eg MeetingItemClass. An exception is raised.

I understand why... But I need a solution on how to find a workaround. I want to process ALL items, even meeting items.

Dim InboxFolder As Outlook.MAPIFolder
Dim FolderItem As Outlook.MailItem
Dim FolderItems As Outlook.Items
Dim ItemNo As Integer

*** removed code that finds the inbox object 'InboxFolder' ***

ItemNo = 1
FolderItems = InboxFolder.Items
FolderItems.Sort("[ReceivedTime]", True)

Do While ItemNo <= FolderItems.Count
    FolderItem = FolderItems(ItemNo)

    *** Do some operations on each inbox-object here ***

    ItemNo = ItemNo + 1
Loop

Answer 1

A possiblility is to define FolderItem As Object and then...

• ...check the type before assigning it to a variable of the specific type

AND

• ...cast it to the specific type in your while loop if necessary

Something like this (not tested):

If TypeOf FolderItem Is MailItem Then
   Dim mailItm As MailItem = DirectCast(FolderItem, MailItem)
   'Do something
ElseIf TypeOf FolderItem Is MeetingItem Then
   Dim meetItm As MeetingItem = DirectCast(FolderItem, MeetingItem)
   'Do something
End If