Private Function StartAutoCAD() As Object
        On Error Resume Next
        Dim AcadApp As Object
        ' Get the active session of AutoCAD using late binding
        AcadApp = GetObject(, "AutoCAD.Application.17.1")
        If Err.Number <> 0 Then
            Err.Clear()
            Shell("c:\Program Files\Common Files\Autodesk Shared\WSCommCntr1.exe", AppWinStyle.NormalFocus)
            ' Create a new session of AutoCAD using late binding
            AcadApp = CreateObject("AutoCAD.Application.17.1")
        End If
        Return AcadApp
    End Function

    Private Sub Test()
        Dim AcadApp As Object
        Dim dbxDoc As Object


        AcadApp = StartAutoCAD()

        AcadApp.Visible = True
        dbxDoc = AcadApp.GetInterfaceObject("ObjectDBX.AxDbDocument.17")
        dbxDoc = AcadApp.activedocument
        Dim ms As Object
        ms = dbxDoc.ModelSpace
        MsgBox(ms.Count.ToString + " objects in in model space")



        Dim entity As Object

        For Each entity In dbxDoc.ModelSpace

            If TypeOf entity Is BlockReference Then
                MsgBox(entity.name)
            End If

        Next entity



        dbxDoc = Nothing
        AcadApp.Application.Quit()
        AcadApp = Nothing

    End Sub