How to programmatically add .xlam addin (as object) to vba?

Question

Hi I'm trying add a reference programnatically as per: How to Add/Remove reference programmatically?

However, the reference I wish to programmatically add is the .xlam file of opensolver.org.

So with the following code:

    Sub AddWS()
  'Create a reference to Windows Script Host, '
  'where you will find FileSystemObject '
  'Reference name: "IWshRuntimeLibrary" '
  'Reference Name in references list: "Windows Script Host Object Model" '
  ReferenceFromFile "C:\Users\path\OpenSolver2.8.5_LinearWin\OpenSolver.xlam"
  End Sub

and function:

Function ReferenceFromFile(strFileName As String) As Boolean
Dim ref As Object
MsgBox (strFileName)

         'On Error GoTo Error_ReferenceFromFile
         'References.AddFromFile (ref)
         'ref = strFileName
         'vbProj.References.AddFromFile strFileName
         References.AddFromFile (strFileName)
         MsgBox (strFileName)
         ReferenceFromFile = True

Exit_ReferenceFromFile:
         Exit Function

Error_ReferenceFromFile:
         ReferenceFromFile = False
         Resume Exit_ReferenceFromFile
End Function

But I get object error 424: "Object required" on the line:

         References.AddFromFile (strFileName)

It is because I do not know how to either:

a. Set the .xlam file as object b. convert the .xlam file to an .ocx file so that it will be read and added to reference.

Does anyone have any suggestions on how to automatically programmatically add the OpenSolver.xlam to microsoft Excel from any random location?*

*For me it works fine if I paste the folder containing the .xlam in:

C:\Program Files (x86)\Microsoft Office\root\Office16\Library

and then open it manually, but I need the users of my code to also be able to run it from a mac without requiring them to manually add the opensolver as a reference before I call it from another module.

As mentioned below the succesfull code indeed adds the OpenSolver.xlam to the references, but I cannot seem to programmatically Mark the checkbox in vba>tools>references.

Does anyone have any suggestions on the code that automatically marks that checkbox before Opensolver in the references, once it is already added?

Answer 1

@Comintern you're my hero of the day! I spent at least 4 hours trying different codes, troubleshooting problems which had risen, and with your simple suggestion on what the problem was, I found the working and exact solution I needed within two minutes! Thank you so much :)

The effective code was:

Private Sub Workbook_Open()

On Error Resume Next
Application.AddIns("OpenSolver").Installed = False
On Error GoTo 0

With Application
    .AddIns.Add "C:\Users\random path\OpenSolver2.8.5_LinearWin\OpenSolver.xlam", False
    .AddIns("OpenSolver").Installed = True
End With

'ThisWorkbook.Close False

End Sub

As was suggested in: Programatically Install Add-In VBA

Hope this still helps those facing identical issues.