Can VBA Reach Across Instances of Excel?

Question

Can an Excel VBA macro, running in one instance of Excel, access the workbooks of another running instance of Excel? For example, I would like to create a list of all workbooks that are open in any running instance of Excel.

Answer 1

Cornelius' answer is partially correct. His code gets the current instance and then makes a new instance. GetObject only ever gets the first instance, no matter how many instances are available. The question I believe is how can you get a specific instance from among many instances.

For a VBA project, make two modules, one code module, and the other as a form with one command button named Command1. You might need to add a reference to Microsoft.Excel.

This code displays all the name of each workbook for each running instance of Excel in the Immediate window.

'------------- Code Module --------------

Option Explicit

Declare Function FindWindowEx Lib "User32" Alias "FindWindowExA" (ByVal hWnd1 As Long, ByVal hWnd2 As Long, ByVal lpsz1 As String, ByVal lpsz2 As String) As Long
Declare Function GetClassName Lib "User32" Alias "GetClassNameA" (ByVal hWnd As Long, ByVal lpClassName As String, ByVal nMaxCount As Long) As Long
Declare Function IIDFromString Lib "ole32" (ByVal lpsz As Long, ByRef lpiid As UUID) As Long
Declare Function AccessibleObjectFromWindow Lib "oleacc" (ByVal hWnd As Long, ByVal dwId As Long, ByRef riid As UUID, ByRef ppvObject As Object) As Long

Type UUID 'GUID
  Data1 As Long
  Data2 As Integer
  Data3 As Integer
  Data4(7) As Byte
End Type

'------------- Form Module --------------

Option Explicit

Const IID_IDispatch As String = "{00020400-0000-0000-C000-000000000046}"
Const OBJID_NATIVEOM As Long = &HFFFFFFF0

'Sub GetAllWorkbookWindowNames()
Sub Command1_Click()
    On Error GoTo MyErrorHandler

    Dim hWndMain As Long
    hWndMain = FindWindowEx(0&, 0&, "XLMAIN", vbNullString)

    Do While hWndMain <> 0
        GetWbkWindows hWndMain
        hWndMain = FindWindowEx(0&, hWndMain, "XLMAIN", vbNullString)
    Loop

    Exit Sub

MyErrorHandler:
    MsgBox "GetAllWorkbookWindowNames" & vbCrLf & vbCrLf & "Err = " & Err.Number & vbCrLf & "Description: " & Err.Description
End Sub

Private Sub GetWbkWindows(ByVal hWndMain As Long)
    On Error GoTo MyErrorHandler

    Dim hWndDesk As Long
    hWndDesk = FindWindowEx(hWndMain, 0&, "XLDESK", vbNullString)

    If hWndDesk <> 0 Then
        Dim hWnd As Long
        hWnd = FindWindowEx(hWndDesk, 0, vbNullString, vbNullString)

        Dim strText As String
        Dim lngRet As Long
        Do While hWnd <> 0
            strText = String$(100, Chr$(0))
            lngRet = GetClassName(hWnd, strText, 100)

            If Left$(strText, lngRet) = "EXCEL7" Then
                GetExcelObjectFromHwnd hWnd
                Exit Sub
            End If

            hWnd = FindWindowEx(hWndDesk, hWnd, vbNullString, vbNullString)
            Loop

        On Error Resume Next
    End If

    Exit Sub

MyErrorHandler:
    MsgBox "GetWbkWindows" & vbCrLf & vbCrLf & "Err = " & Err.Number & vbCrLf & "Description: " & Err.Description
End Sub

Public Function GetExcelObjectFromHwnd(ByVal hWnd As Long) As Boolean
    On Error GoTo MyErrorHandler

    Dim fOk As Boolean
    fOk = False

    Dim iid As UUID
    Call IIDFromString(StrPtr(IID_IDispatch), iid)

    Dim obj As Object
    If AccessibleObjectFromWindow(hWnd, OBJID_NATIVEOM, iid, obj) = 0 Then 'S_OK
        Dim objApp As Excel.Application
        Set objApp = obj.Application
        Debug.Print objApp.Workbooks(1).Name

        Dim myWorksheet As Worksheet
        For Each myWorksheet In objApp.Workbooks(1).Worksheets
            Debug.Print "     " & myWorksheet.Name
            DoEvents
        Next

        fOk = True
    End If

    GetExcelObjectFromHwnd = fOk

    Exit Function

MyErrorHandler:
    MsgBox "GetExcelObjectFromHwnd" & vbCrLf & vbCrLf & "Err = " & Err.Number & vbCrLf & "Description: " & Err.Description
End Function

Answer 2

I believe that VBA is more powerful than Charles thinks ;)

If there is only some tricky way to point to the specific instance from GetObject and CreateObject we'll have your problem solved!

EDIT:

If you're the creator of all the instances there should be no problems with things like listing workbooks. Take a look on this code:

Sub Excels()
    Dim currentExcel As Excel.Application
    Dim newExcel As Excel.Application

    Set currentExcel = GetObject(, "excel.application")
    Set newExcel = CreateObject("excel.application")

    newExcel.Visible = True
    newExcel.Workbooks.Add
    'and so on...
End Sub

Answer 3

I think that within VBA you can get access to the application object in another running instance . If you know the name of a workbook open within the other instance, then you can get a reference to the application object. See Allen Waytt's page

The last part,

Dim xlApp As Excel.Application
Set xlApp = GetObject("c:\\mypath\\ExampleBook.xlsx").Application

Allowed me to get a pointer to the application object of the instance that had ExampleBook.xlsx open.

I believe "ExampleBook" needs to be the full path, at least in Excel 2010. I'm currently experimenting with this myself, so I will try and update as I get more details.

Presumably there may be complications if separate instances have the same workbook open, but only one may have write access.

Answer 4

Thanks to this great post I had a routine to find return an array of all Excel applications currently running on the machine. Trouble is that I've just upgraded to Office 2013 64 bit and it all went wrong.

There is the usual faff of converting ... Declare Function ... into ... Declare PtrSafe Function ... , which is well documented elsewhere. However, what I couldn't find any documentation on is that fact that the window hierarchy ('XLMAIN' -> 'XLDESK' -> 'EXCEL7') that the original code expects has changed following this upgrade. For anyone following in my footsteps, to save you an afternoon of digging around, I thought I'd post my updated script. It's hard to test, but I think it should be backwards compatible too for good measure.

Option Explicit

#If Win64 Then

    Private Declare PtrSafe Function FindWindowEx Lib "user32" Alias "FindWindowExA" (ByVal hWnd1 As LongPtr, ByVal hWnd2 As LongPtr, ByVal lpsz1 As String, ByVal lpsz2 As String) As LongPtr
    Private Declare PtrSafe Function GetClassName Lib "user32" Alias "GetClassNameA" (ByVal Hwnd As LongPtr, ByVal lpClassName As String, ByVal nMaxCount As LongPtr) As LongPtr
    Private Declare PtrSafe Function IIDFromString Lib "ole32" (ByVal lpsz As LongPtr, ByRef lpiid As UUID) As LongPtr
    Private Declare PtrSafe Function AccessibleObjectFromWindow Lib "oleacc" (ByVal Hwnd As LongPtr, ByVal dwId As LongPtr, ByRef riid As UUID, ByRef ppvObject As Object) As LongPtr

#Else

    Private Declare Function FindWindowEx Lib "user32" Alias "FindWindowExA" (ByVal hWnd1 As Long, ByVal hWnd2 As Long, ByVal lpsz1 As String, ByVal lpsz2 As String) As Long
    Private Declare Function GetClassName Lib "user32" Alias "GetClassNameA" (ByVal hwnd As Long, ByVal lpClassName As String, ByVal nMaxCount As Long) As Long
    Private Declare Function IIDFromString Lib "ole32" (ByVal lpsz As Long, ByRef lpiid As UUID) As Long
    Private Declare Function AccessibleObjectFromWindow Lib "oleacc" (ByVal hwnd As Long, ByVal dwId As Long, ByRef riid As UUID, ByRef ppvObject As Object) As Long

#End If

Type UUID 'GUID
    Data1 As Long
    Data2 As Integer
    Data3 As Integer
    Data4(7) As Byte
End Type

Const IID_IDispatch As String = "{00020400-0000-0000-C000-000000000046}"
Const OBJID_NATIVEOM As LongPtr = &HFFFFFFF0

' Run as entry point of example
Public Sub Test()

Dim i As Long
Dim xlApps() As Application

    If GetAllExcelInstances(xlApps) Then
        For i = LBound(xlApps) To UBound(xlApps)
            If xlApps(i).Workbooks(1).Name <> ThisWorkbook.Name Then
                MsgBox (xlApps(i).Workbooks(1).Name)
            End If
        Next
    End If

End Sub

' Actual public facing function to be called in other code
Public Function GetAllExcelInstances(xlApps() As Application) As Long

On Error GoTo MyErrorHandler

Dim n As Long
#If Win64 Then
    Dim hWndMain As LongPtr
#Else
    Dim hWndMain As Long
#End If
Dim app As Application

    ' Cater for 100 potential Excel instances, clearly could be better
    ReDim xlApps(1 To 100)

    hWndMain = FindWindowEx(0&, 0&, "XLMAIN", vbNullString)

    Do While hWndMain <> 0
        Set app = GetExcelObjectFromHwnd(hWndMain)
        If Not (app Is Nothing) Then
            If n = 0 Then
                n = n + 1
                Set xlApps(n) = app
            ElseIf checkHwnds(xlApps, app.Hwnd) Then
                n = n + 1
                Set xlApps(n) = app
            End If
        End If
        hWndMain = FindWindowEx(0&, hWndMain, "XLMAIN", vbNullString)
    Loop

    If n Then
        ReDim Preserve xlApps(1 To n)
        GetAllExcelInstances = n
    Else
        Erase xlApps
    End If

    Exit Function

MyErrorHandler:
    MsgBox "GetAllExcelInstances" & vbCrLf & vbCrLf & "Err = " & Err.Number & vbCrLf & "Description: " & Err.Description

End Function

#If Win64 Then
    Private Function checkHwnds(xlApps() As Application, Hwnd As LongPtr) As Boolean
#Else
    Private Function checkHwnds(xlApps() As Application, Hwnd As Long) As Boolean
#End If

Dim i As Integer

    For i = LBound(xlApps) To UBound(xlApps)
        If xlApps(i).Hwnd = Hwnd Then
            checkHwnds = False
            Exit Function
        End If
    Next i

    checkHwnds = True

End Function

#If Win64 Then
    Private Function GetExcelObjectFromHwnd(ByVal hWndMain As LongPtr) As Application
#Else
    Private Function GetExcelObjectFromHwnd(ByVal hWndMain As Long) As Application
#End If

On Error GoTo MyErrorHandler

#If Win64 Then
    Dim hWndDesk As LongPtr
    Dim Hwnd As LongPtr
#Else
    Dim hWndDesk As Long
    Dim Hwnd As Long
#End If
Dim strText As String
Dim lngRet As Long
Dim iid As UUID
Dim obj As Object

    hWndDesk = FindWindowEx(hWndMain, 0&, "XLDESK", vbNullString)

    If hWndDesk <> 0 Then

        Hwnd = FindWindowEx(hWndDesk, 0, vbNullString, vbNullString)

        Do While Hwnd <> 0

        strText = String$(100, Chr$(0))
        lngRet = CLng(GetClassName(Hwnd, strText, 100))

        If Left$(strText, lngRet) = "EXCEL7" Then

            Call IIDFromString(StrPtr(IID_IDispatch), iid)

            If AccessibleObjectFromWindow(Hwnd, OBJID_NATIVEOM, iid, obj) = 0 Then 'S_OK

                Set GetExcelObjectFromHwnd = obj.Application
                Exit Function

            End If

        End If

        Hwnd = FindWindowEx(hWndDesk, Hwnd, vbNullString, vbNullString)
        Loop

        On Error Resume Next

    End If

    Exit Function

MyErrorHandler:
    MsgBox "GetExcelObjectFromHwnd" & vbCrLf & vbCrLf & "Err = " & Err.Number & vbCrLf & "Description: " & Err.Description

End Function

Answer 5

I had a similar problem/goal.

And I got ForEachLoops answer working, but there is a change that needs made. In the bottom function (GetExcelObjectFromHwnd), he used the workbook index of 1 in both debug.print commands. The result is you only see the first WB.

So I took his code, and put a for loop inside GetExcelObjectFromHwnd, and changed the 1 to a counter. the result is I can get ALL active excel workbooks and return the information I need to reach across instances of Excel and access other WB's.

And I created a Type to simplify retrieving of the info and pass it back to the calling subroutine:

Type TargetWBType
    name As String
    returnObj As Object
    returnApp As Excel.Application
    returnWBIndex As Integer
End Type

For name I simply used the base filename, eg "example.xls". This snippet proves the functionality by spitting out the value of A6 on every WS of the target WB. Like so:

Dim targetWB As TargetWBType
targetWB.name = "example.xls"

Call GetAllWorkbookWindowNames(targetWB)

If Not targetWB.returnObj Is Nothing Then
    Set targetWB.returnApp = targetWB.returnObj.Application
    Dim ws As Worksheet
    For Each ws In targetWB.returnApp.Workbooks(targetWB.returnWBIndex).Worksheets
        MsgBox ws.Range("A6").Value
    Next
Else
    MsgBox "Target WB Not found"
End If

So now the ENTIRE module that ForEachLoop originally made looks like this, and I've indicated the changes I made. It does have a msgbox popup, whcih I left in the snippet for debugging purposes. Strip that out once it's finding your target. The code:

Declare Function FindWindowEx Lib "User32" Alias "FindWindowExA" (ByVal hWnd1 As Long, ByVal hWnd2 As Long, ByVal lpsz1 As String, ByVal lpsz2 As String) As Long
Declare Function GetClassName Lib "User32" Alias "GetClassNameA" (ByVal hWnd As Long, ByVal lpClassName As String, ByVal nMaxCount As Long) As Long
Declare Function IIDFromString Lib "ole32" (ByVal lpsz As Long, ByRef lpiid As UUID) As Long
Declare Function AccessibleObjectFromWindow Lib "oleacc" (ByVal hWnd As Long, ByVal dwId As Long, ByRef riid As UUID, ByRef ppvObject As Object) As Long

Type UUID 'GUID
  Data1 As Long
  Data2 As Integer
  Data3 As Integer
  Data4(7) As Byte
End Type

'------------- Form Module --------------

Option Explicit

Const IID_IDispatch As String = "{00020400-0000-0000-C000-000000000046}"
Const OBJID_NATIVEOM As Long = &HFFFFFFF0

'My code: added targetWB
Sub GetAllWorkbookWindowNames(targetWB As TargetWBType)
    On Error GoTo MyErrorHandler

    Dim hWndMain As Long
    hWndMain = FindWindowEx(0&, 0&, "XLMAIN", vbNullString)

    Do While hWndMain <> 0
        GetWbkWindows hWndMain, targetWB 'My code: added targetWB
        hWndMain = FindWindowEx(0&, hWndMain, "XLMAIN", vbNullString)
    Loop

    Exit Sub

MyErrorHandler:
    MsgBox "GetAllWorkbookWindowNames" & vbCrLf & vbCrLf & "Err = " & Err.Number & vbCrLf & "Description: " & Err.Description
End Sub

'My code: added targetWB
Private Sub GetWbkWindows(ByVal hWndMain As Long, targetWB As TargetWBType)
    On Error GoTo MyErrorHandler

    Dim hWndDesk As Long
    hWndDesk = FindWindowEx(hWndMain, 0&, "XLDESK", vbNullString)

    If hWndDesk <> 0 Then
        Dim hWnd As Long
        hWnd = FindWindowEx(hWndDesk, 0, vbNullString, vbNullString)

        Dim strText As String
        Dim lngRet As Long
        Do While hWnd <> 0
            strText = String$(100, Chr$(0))
            lngRet = GetClassName(hWnd, strText, 100)

            If Left$(strText, lngRet) = "EXCEL7" Then
                GetExcelObjectFromHwnd hWnd, targetWB 'My code: added targetWB
                Exit Sub
            End If

            hWnd = FindWindowEx(hWndDesk, hWnd, vbNullString, vbNullString)
            Loop

        On Error Resume Next
    End If

    Exit Sub

MyErrorHandler:
    MsgBox "GetWbkWindows" & vbCrLf & vbCrLf & "Err = " & Err.Number & vbCrLf & "Description: " & Err.Description
End Sub

'My code: added targetWB
Public Function GetExcelObjectFromHwnd(ByVal hWnd As Long, targetWB As TargetWBType) As Boolean
    On Error GoTo MyErrorHandler

    Dim fOk As Boolean
    fOk = False

    Dim iid As UUID
    Call IIDFromString(StrPtr(IID_IDispatch), iid)

    Dim obj As Object
    If AccessibleObjectFromWindow(hWnd, OBJID_NATIVEOM, iid, obj) = 0 Then 'S_OK
        Dim objApp As Excel.Application
        Set objApp = obj.Application

        'My code
        Dim wbCount As Integer
        For wbCount = 1 To objApp.Workbooks.Count
        'End my code

            'Not my code
            Debug.Print objApp.Workbooks(wbCount).name

            'My code
                If LCase(objApp.Workbooks(wbCount).name) = LCase(targetWB.name) Then
                    MsgBox ("Found target: " & targetWB.name)
                    Set targetWB.returnObj = obj
                    targetWB.returnWBIndex = wbCount
                End If
            'End My code

            'Not my code
            Dim myWorksheet As Worksheet
            For Each myWorksheet In objApp.Workbooks(wbCount).Worksheets
                Debug.Print "     " & myWorksheet.name
                DoEvents
            Next

        'My code
        Next
        'Not my code

        fOk = True
    End If

    GetExcelObjectFromHwnd = fOk

    Exit Function

MyErrorHandler:
    MsgBox "GetExcelObjectFromHwnd" & vbCrLf & vbCrLf & "Err = " & Err.Number & vbCrLf & "Description: " & Err.Description
End Function

I repeat, this works, and using the variables within the TargetWB type I am reliably accessing workbooks and worksheets across instances of Excel.

The only potential problem I see with my solution, is if you have multiple WB's with the same name. Right now, I believe it would return the last instance of that name. If we add an Exit For into the If Then I believe it will instead return the first instance of it. I didn't test this part thouroughly as in my application there is only ever one instance of the file open.

Answer 6

Just to add to James MacAdie's answer, I think you do the redim too late because in the checkHwnds function you end up with an out of range error as you're trying to check values up to 100 even though you haven't yet populated the array fully? I modified the code to the below and it's now working for me.

' Actual public facing function to be called in other code
Public Function GetAllExcelInstances(xlApps() As Application) As Long

On Error GoTo MyErrorHandler

Dim n As Long
#If Win64 Then
    Dim hWndMain As LongPtr
#Else
    Dim hWndMain As Long
#End If
Dim app As Application

' Cater for 100 potential Excel instances, clearly could be better
ReDim xlApps(1 To 100)

hWndMain = FindWindowEx(0&, 0&, "XLMAIN", vbNullString)

Do While hWndMain <> 0
    Set app = GetExcelObjectFromHwnd(hWndMain)
    If Not (app Is Nothing) Then
        If n = 0 Then
            n = n + 1
            ReDim Preserve xlApps(1 To n)
            Set xlApps(n) = app
        ElseIf checkHwnds(xlApps, app.Hwnd) Then
            n = n + 1
            ReDim Preserve xlApps(1 To n)
            Set xlApps(n) = app
        End If
    End If
    hWndMain = FindWindowEx(0&, hWndMain, "XLMAIN", vbNullString)
Loop

If n Then
    GetAllExcelInstances = n
Else
    Erase xlApps
End If

Exit Function

MyErrorHandler:
    MsgBox "GetAllExcelInstances" & vbCrLf & vbCrLf & "Err = " & Err.Number & vbCrLf & "Description: " & Err.Description

End Function

Answer 7

我认为仅使用VBA是不可能的，因为您可以访问的最高级别的对象是Application对象，它是Excel的当前实例。