Using MS Access to run code in excel vba

Question

I pull a query off SQL Server using an access front-end. I then export the recordset to a new Excel workbook. I want to then use excel to run code that I have in Access. It

Answer 1

Base on Matt Hall's answer but altered to show how you can, from Access:

• Invoke an Excel module apart from ThisWorkbook;
• Invoke Excel Subs or retrieve a value from an Excel Function; and
• Fetch the atlered values of parameters passed by reference.

In a custom module, named basTextModule, in Excel:

Public Sub ShowCoolMessage()
 MsgBox "cool"
End Sub

' Add02 is explictly ByRef (the default in VBA) to show that
' the parameter will be altered and have its value changed even for
' prodedures higher up the call stack.
Public Function GetCoolAmount(Add01 As Variant, _
                            Optional ByRef Add02 As Integer) As Integer
  Add02 = Add02 + 1
  GetCoolAmount = 10 + Add01 + Add02
End Function

In Access:

• Set a reference to Excel (VBA IDE > Tools > Reference ... Microsoft Excel 16.0 Object Library).
• Then create a (somewhat) generic RunExcelCode ...

For parameters passed by reference to work:

• Note from Microsoft Docs, Application.Run method (Excel) that when you pass parameters to the Excel Sub or Function "You cannot use named arguments with this method. Arguments must be passed by position".

• When declaring excelApp use Object rather than Excel.Application in order to ensure that the value of any parameters passed by reference to excelApp.Run can be retrieved. Source: Jaafar Tribak "Application.Run .. (Argument Passed ByRef)" at https://www.mrexcel.com/board/threads/application-run-argument-passed-byref.998132/post-4790961

• In the called sub or Function the parameters (apart from the first ModuleAndSubOrFunctionName) must have a data type that match the datatype of the parmaters for the calling module or function. They can be variants or a specific datatype. E.g, and for illustrative purposes, Arg02 is an Integer and so must the second argument of GetCoolAmount when RunExcelCode(WorkbookPathAndFileName, "basTestModule.GetCoolAmount" ...) is used.

  However to make your RunExcelCode more generic it may be wise to ensure Arg01, Arg02, ... Arg30 paramters are all variants; and therefore the parameters of your ultimately called sub or function are also variants, for example ...

  Public Function GetCoolAmount(Add01 As Variant, _
                            Optional ByRef Add02 As Variant) As Integer
  ...
  

Public Function RunExcelCode(WorkbookPathAndFileName As String, _
                             ModuleAndSubOrFunctionName As String, _
                             Optional ByRef Arg01 As Variant, _
                             Optional ByRef Arg02 As Integer) As Variant
  ' Must be Object, not Excel.Application, to allow for parameters pass by reference
  Dim excelApp  As Object
  Dim workbook  As Excel.workbook
  
  Dim Result As Variant
  
On Error GoTo HandleErr
  
  ' Can be Excel.Application if excelApp previously declared as Object
  Set excelApp = New Excel.Application
  
'  excelApp.Visible = True ' For debugging
  
  Set workbook = excelApp.Workbooks.Open(WorkbookPathAndFileName)
  
  ' Get a value from a function or,
  ' if it is a sub a zero length string "" will be returned
  Result = excelApp.Run(ModuleAndSubOrFunctionName, Arg01, Arg02)
  
  RunExcelCode = Result

ExitHere:
  workbook.Close
  excelApp.Quit
  Set workbook = Nothing
  Set excelApp = Nothing
Exit Function

HandleErr:
  Select Case Err.number
    Case Else
      MsgBox "Error " & Err.number & ": " & Err.Description, _
        vbCritical, "RunExcelCode"
  End Select
  Resume ExitHere
End Function

Testing (from Access), calling a Sub and a Function:

Private Sub TestRunExcelCode()
  Dim WorkbookPathAndFileName  As String
  Dim Result As Variant
  
  WorkbookPathAndFileName = "C:\Users\YourName\Documents\MyWorkbook.xlsm"
  
  '   Run a sub
  Result = RunExcelCode(WorkbookPathAndFileName, "basTestModule.ShowCoolMessage")
  If IsNull(Result) Then
    Debug.Print "{Null}"
  ElseIf Result = "" Then
    Debug.Print "{Zero length string}"
  Else
    Debug.Print Result
  End If

  ' Will output "{Zero length string}"
  
  ' Get a value from a function
  Dim Arg02 As Integer
  Arg02 = 1
  Debug.Print "Arg02 Before: " & Arg02
  Result = RunExcelCode(WorkbookPathAndFileName, _
                      "basTestModule.GetCoolAmount", 1, Arg02)
  Debug.Print "Arg02 After : " & Arg02  ' Value will have changed, as desired.
  Debug.Print "Result      : " & Result
  
End Sub

Edit 01: Major change to make code more generic.

Edit 02: Major change to handle paramaters passed by reference.

Edit 03: Added details in the case "to make your RunExcelCode more generic".