Imports System.IO
Imports System.Runtime.InteropServices

Module Example
    <STAThread()> _
    Sub Main()

        Dim objApplication As SolidEdgeFramework.Application = Nothing
        Dim objAssemblyDocument As SolidEdgeAssembly.AssemblyDocument = Nothing
        Dim objOccurrences As SolidEdgeAssembly.Occurrences = Nothing
        Dim objOccurrence As SolidEdgeAssembly.Occurrence = Nothing

        Try
            OleMessageFilter.Register()

            objApplication = Marshal.GetActiveObject("SolidEdge.Application")
            objAssemblyDocument = objApplication.ActiveDocument
            objOccurrences = objAssemblyDocument.Occurrences

            For Each objOccurrence In objOccurrences
                If (objOccurrence.DisplayCenterline = True) Then
                    objOccurrence.DisplayCenterline = False
                Else
                    objOccurrence.DisplayCenterline = True
                End If
            Next

        Catch ex As Exception
            Console.WriteLine(ex.Message)
        Finally
            OleMessageFilter.Revoke()
        End Try
    End Sub
End Module