VBA call VSTO Method

VBA call VSTO Method

Sub CallVSTOMethod()
    Dim addIn As COMAddIn
    Dim automationObject As Object
    Set addIn = Application.COMAddIns("AddInNameInRegistry")
    Set automationObject = addIn.Object
    Dim bSuccess As Boolean
    Dim sEngineID As String
    Dim sDisplayName As String
    sEngineID = ""
    bSuccess = automationObject.IsAuthorizedUser(sEngineID, sDisplayName)
    MsgBox (bSuccess & vbCrLf & sEngineID & vbCrLf & sDisplayName)
    Set automationObject = Nothing
    Set addIn = Nothing
End Sub

Note: If not sure about the "AddInName", you can use below method to enumerate all the AddIns loaded.

    Dim addIn As COMAddIn
    Dim automationObject As Object
   
    Dim nAddInsCount As Integer
    nAddInsCount = Application.COMAddIns.Count
   
    For Each addIn In Application.COMAddIns
        MsgBox(addIn.ProgId)    'This is the AddIn name you registered in Registry
    Next

    Besides, you can also use index to refer to a particular AddIn as follow:
    Set addIn = Application.COMAddIns(1)