I'm developing a VSTO (second edition) addin for Outlook. One of my
customers gets the following error:

"System.InvalidCastException: Specified cast is not valid.
at
System.Runtime.InteropServices.Marshal.ThrowExcept ionForHRInternal
(Int32 errorCode, IntPtr errorInfo)
at
System.Runtime.InteropServices.CustomMarshalers.En umerableViewOfDispatch.GetEnumerator
()
at System.Collections.IEnumerable.GetEnumerator() "

when looping through the items in the calendar folder.

Dim oFolder As MsOutlook.MAPIFolder = oSession.GetDefaultFolder
(Outlook.OlDefaultFolders.olFolderCalendar)
Dim oItems As MsOutlook.Items = m_oFolder.Items

For Each oItem As Object In oItems
....
Next

Anyone who has any clue about the cause of this error?

What line is the exception thrown on? Is it in the For Each line?

Does the exception get thrown if the code is changed to use a normal For
loop with a loop counter?

Dim count as Integer = oItems.Count
Dim i As Integer
For i = 1 To count
' code here
Next

--
Ken Slovak
[MVP - Outlook]
http://www.slovaktech.com
Author: Professional Programming Outlook 2007.
Reminder Manager, Extended Reminders, Attachment Options.
http://www.slovaktech.com/products.htm


"Janni" wrote in message
...
I'm developing a VSTO (second edition) addin for Outlook. One of my
customers gets the following error:

"System.InvalidCastException: Specified cast is not valid.
at
System.Runtime.InteropServices.Marshal.ThrowExcept ionForHRInternal
(Int32 errorCode, IntPtr errorInfo)
at
System.Runtime.InteropServices.CustomMarshalers.En umerableViewOfDispatch.GetEnumerator
()
at System.Collections.IEnumerable.GetEnumerator() "

when looping through the items in the calendar folder.

Dim oFolder As MsOutlook.MAPIFolder = oSession.GetDefaultFolder
(Outlook.OlDefaultFolders.olFolderCalendar)
Dim oItems As MsOutlook.Items = m_oFolder.Items

For Each oItem As Object In oItems
...
Next

Anyone who has any clue about the cause of this error?