Run code when email shows up in Outlook subfolder

Question

I implemented the code offered as an answer here to run a Python script every time an email with subject "Blah" came into my Inbox.

I'm trying to implement code that would run a macro on a separate Excel spreadsheet titled main.xlsx every time an email with subject "Woo" comes into a subfolder in my inbox.

To grab all the items in this subfolder I have

Set productionItems = objectNS.GetDefaultFolder(olFolderInbox).Folders("Production Emails").Items

As a step towards the goal, I want to generate a message with Debug.Print (or message box) every time a mail called "Woo" arrives in my "Production Emails" subfolder of the Inbox.

I don't get the Debug.Print message "Arrived3", which I expect, when I send an email with subject "Woo" to myself.

Option Explicit
Private WithEvents inboxItems As Outlook.Items
Private WithEvents productionItems As Outlook.Items [!!!]
Public Sub Application_Startup()
    Dim outlookApp As Outlook.Application
    Dim objectNS As Outlook.NameSpace
    Set outlookApp = Outlook.Application
    Set objectNS = outlookApp.GetNamespace("MAPI")
    Set inboxItems = objectNS.GetDefaultFolder(olFolderInbox).Items
    Set productionItems = objectNS.GetDefaultFolder(olFolderInbox).Folders("Production Emails").Items
End Sub

Private Sub inboxItems_ItemAdd(ByVal Item As Object)
On Error GoTo ErrorHandler
Dim Msg As Outlook.MailItem
Dim MessageInfo
Dim Result
If TypeName(Item) = "MailItem" Then
    Debug.Print "Arrived3"
    If Item.Subject = "Blah" Then
        Const PyExe = "C:\...\python.exe"
        Const PyScript = "R:\...\main.py"
        
        Dim objShell As Object, cmd As String
        Set objShell = CreateObject("Wscript.Shell")
        
        cmd = PyExe & " " & PyScript
        Debug.Print cmd
        
        objShell.Run cmd
        objShell.exec cmd
        
        MsgBox objShell.exec(cmd).StdOut.ReadAll
    End If
End If
ExitNewItem:
    Exit Sub
ErrorHandler:
    MsgBox Err.Number & " - " & Err.Description
    Resume ExitNewItem
End Sub

Answer 1

First of all, in the code you set up the ItemAdd event handler for the Inbox folder, not a subfolder. You need to change the name of event handler if you want to receive events from a subfolder.

You need to create a new Outlook Application instance in the code if you automate it from Excel:

Option Explicit

Private WithEvents inboxItems As Outlook.Items
Private WithEvents productionItems As Outlook.Items

Public Sub Application_Startup()
    Dim outlookApp As Outlook.Application
    Dim objectNS As Outlook.NameSpace

    Set outlookApp = New Outlook.Application

    Set objectNS = outlookApp.GetNamespace("MAPI")
    Set inboxItems = objectNS.GetDefaultFolder(olFolderInbox).Items
    Set productionItems = objectNS.GetDefaultFolder(olFolderInbox).Folders("Production Emails").Items
End Sub

Private Sub productionItems_ItemAdd(ByVal Item As Object)
On Error GoTo ErrorHandler
Dim Msg As Outlook.MailItem
Dim MessageInfo
Dim Result
If TypeName(Item) = "MailItem" Then
    Debug.Print "Arrived3"
    If Item.Subject = "Blah" Then
        Const PyExe = "C:\...\python.exe"
        Const PyScript = "R:\...\main.py"
        
        Dim objShell As Object, cmd As String
        Set objShell = CreateObject("Wscript.Shell")
        
        cmd = PyExe & " " & PyScript
        Debug.Print cmd
        
        objShell.Run cmd
        objShell.exec cmd
        
        MsgBox objShell.exec(cmd).StdOut.ReadAll
    End If
End If
ExitNewItem:
    Exit Sub
ErrorHandler:
    MsgBox Err.Number & " - " & Err.Description
    Resume ExitNewItem
End Sub

It seems your VBA macro was designed to be run from Outlook, not Excel. Don't forget that you need to call the Application_Startup method from Excel.