Having multiple Excel instances launched, how can I get the Application Object for all of them?

Question

I want to use something similar to GetObject(,"Excel.Application") to get back the application I created.

I call CreateObject("Excel.Application") to create Excel instances. Later if the VBA project resets, due to debugging and coding, the Application object variables are lost but the Excel instances are running in the background. Kind of a memory leak situation.

I want to re-attach to either re-use (preferred way) or close them.

Answer 1

To list the running instances of Excel:

#If VBA7 Then
  Private Declare PtrSafe Function AccessibleObjectFromWindow Lib "oleacc" ( _
    ByVal hwnd As LongPtr, ByVal dwId As Long, riid As Any, ppvObject As Object) As Long

  Private Declare PtrSafe Function FindWindowExA Lib "user32" ( _
    ByVal hwndParent As LongPtr, ByVal hwndChildAfter As LongPtr, _
    ByVal lpszClass As String, ByVal lpszWindow As String) As LongPtr
#Else
  Private Declare Function AccessibleObjectFromWindow Lib "oleacc" ( _
    ByVal hwnd As Long, ByVal dwId As Long, riid As Any, ppvObject As Object) As Long

  Private Declare Function FindWindowExA Lib "user32" ( _
    ByVal hwndParent As Long, ByVal hwndChildAfter As Long, _
    ByVal lpszClass As String, ByVal lpszWindow As String) As Long
#End If

Sub Test()
  Dim xl As Application
  For Each xl In GetExcelInstances()
    Debug.Print "Handle: " & xl.ActiveWorkbook.FullName
  Next
End Sub

Public Function GetExcelInstances() As Collection
  Dim guid&(0 To 3), acc As Object, hwnd, hwnd2, hwnd3
  guid(0) = &H20400
  guid(1) = &H0
  guid(2) = &HC0
  guid(3) = &H46000000

  Set GetExcelInstances = New Collection
  Do
    hwnd = FindWindowExA(0, hwnd, "XLMAIN", vbNullString)
    If hwnd = 0 Then Exit Do
    hwnd2 = FindWindowExA(hwnd, 0, "XLDESK", vbNullString)
    hwnd3 = FindWindowExA(hwnd2, 0, "EXCEL7", vbNullString)
    If AccessibleObjectFromWindow(hwnd3, &HFFFFFFF0, guid(0), acc) = 0 Then
      GetExcelInstances.Add acc.Application
    End If
  Loop
End Function