How do I reference an ItemProperty of a generic VBA Object variable by the property name?

I have an Outlook 2003 VBA application that includes something like the following code in a particular class:

Sub SaveAttributes(objMail as Outlook.MailItem)
Dim Field As String  
Dim SaveForLater As String  

Field = "Subject"  
SaveForLater = objMail.ItemProperties(Field).Value  

...  

End Sub  

I'd like to extend the app to handle MeetingItems, etc, and I thought to modify the code like so:

Sub SaveAttributes(objGeneric as Object)  
...  

This modification generates a runtime error 91, 'Object variable or With block not set', at the line assigning SaveForLater.

The runtime error disappears if I modify that line like so:

SaveForLater = objGeneric.ItemProperties.Item("Subject").Value

But it oddly reappears if I modify that line like so:

SaveForLater = objGeneric.ItemProperties.Item(Field).Value

Why do these lines behave differently?开发者_开发问答 And what is the proper way to reference a generic Object's item properties by name, where the name is a string variable?

This worked for me:

Sub SaveAttributes(objGeneric As Object)
    Dim Field As String
    Dim SaveForLater As String
    Dim itemProps As Outlook.ItemProperties
    Dim itemProp As Outlook.ItemProperty

    Field = "Subject"

    Set itemProps = objGeneric.ItemProperties
    Set itemProp = itemProps.Item(Field)

    SaveForLater = itemProp.Value

End Sub