' Show how to use LockElements
' It locks and unlocks the urls element.
Shared Sub LockElements()

    Try
        ' Get the current configuration file.
        Dim config _
        As System.Configuration.Configuration = _
        ConfigurationManager.OpenExeConfiguration( _
        ConfigurationUserLevel.None)

        ' Get the MyUrls section.
        Dim myUrlsSection As UrlsSection = _
        config.GetSection("MyUrls")

        If myUrlsSection Is Nothing Then
            Console.WriteLine("Failed to load UrlsSection.")
        Else
            ' Get MyUrls section LockElements collection.
            Dim lockElements _
            As ConfigurationLockCollection = _
            myUrlsSection.LockElements

            ' Get MyUrls section LockElements collection 
            ' enumerator.
            Dim lockElementEnum As IEnumerator = _
            lockElements.GetEnumerator()

            ' Position the collection index.
            lockElementEnum.MoveNext()

            If lockElements.Contains("urls") Then
                ' Remove the lock on the urls element.
                lockElements.Remove("urls")
            Else
                ' Add the lock on the urls element.
                lockElements.Add("urls")
            End If
            ' Save the change.
            config.Save(ConfigurationSaveMode.Full)
        End If

    Catch err As ConfigurationErrorsException
        Console.WriteLine("[LockElements: {0}]", _
        err.ToString())
    End Try

End Sub