Programmatically dismiss a MsgBox - vba

Question

I have a master macro in an Excel file, 'file A' that opens another Excel file, 'file B'. On open, an add-in imports data into 'file B'. I would like to close 'file B' once the add-in is finished importing, and I'm looking for the best way to do that.
I've written the code to open 'file B' (which triggers the add-in automatically) and to close the file, but when the add-in is finished, it opens a MsgBox to notify the user. I'm trying to completely automate an internal process, so dismissing the MsgBox programmatically would be ideal.
Is it possible to dismiss a MsgBox through VBA? I'm aware that I can create timed MsgBoxes in VBA but I'm not creating this MsgBox (the add-in is); I just want to dismiss it. I'm open to creating a Word file and calling a macro from that if required, but would prefer not to use SendKeys.

Answer 1

Since the "add-in" and Excel/VBA run in the same context, we cannot launch it and monitor its message-box within the same VBA application, because each VBA application is a single-threaded process. Fortunately however, there is a solution that can exploit the fact that different VBA applications run in different contexts, so they can run in parallel.
My suggested solution is to create a MS-Word document that is dedicated to monitoring and closing that message box. We need this in Word (or any other office application) in order to make the monitoring code and the addin's code run in parallel, in different contexts.
1- create a Word macro-enable document, named mboxKiller.docm and place it in some folder; i.e. C:\SO in my example. place this code in ThisDocument and save:
Private Declare PtrSafe Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Private Declare PtrSafe Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
Public Sub WaitAndKillWindow()
On Error Resume Next
Dim h As Long: h = FindWindow(vbNullString, "Microsoft Excel")
If h <> 0 Then SendMessage h, 16, 0, 0 ' <-- WM_Close
Application.OnTime Now + TimeSerial(0, 0, 1), "WaitAndKillWindow"
End Sub
Private Sub Document_Open()
WaitAndKillWindow
End Sub
2- In the Excel workbook's VBA, create a class module, named mboxKiller with this code:
Private killerDoc As Object
Private Sub Class_Initialize()
On Error Resume Next
Set killerDoc = CreateObject("Word.Application").Documents.Open(Filename:="C:\SO\mboxKiller.docm", ReadOnly:=True)
If Err.Number <> 0 Then
If Not killerDoc Is Nothing Then killerDoc.Close False
Set killerDoc = Nothing
MsgBox "could not lauch The mboxKiller killer. The message-box shall be closed manuallt by the user."
End If
End Sub
Private Sub Class_Terminate()
On Error Resume Next
If Not killerDoc Is Nothing Then killerDoc.Application.Quit False
End Sub
3- Testing and Usage. In a normal class Module, place the following code and test the procedure
Sub Test() ' <-- run this for testing after finishing the setup
Dim killer: Set killer = New mboxKiller
simulateAddin
simulateAddin
simulateAddin
End Sub
' Procedure supposed to do some calculation then display a message box
Private Sub simulateAddin()
Dim i As Long
For i = 0 To 1000: DoEvents: Next ' simulates some calculations
MsgBox "This is a message box to simulate the message box of the addin." & VbCrLf & _
"It will be automatically closed by the Word app mboxKiller"
End Sub

Answer 2

VBA also has the ability to temporarily dismiss alerts.
Application.DisplayAlerts = False
'while you run your code here, no alerts will be displayed
Application.DisplayAlerts = True