' Create a section whose name is 
' MyUrls that contains a nested collection as 
' defined by the UrlsSection class.
Shared Sub CreateSection()
    Dim sectionName As String = "MyUrls"

    Try

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

        Dim urlsSection As UrlsSection

        ' Create the section whose name
        ' attribute isMyUrls in 
        ' <configSections>.
        ' Also, create the related target section 
        ' MyUrls in <configuration>.
        If config.Sections(sectionName) Is Nothing Then
            urlsSection = New UrlsSection()

            ' Change the default values of 
            ' the simple element.
            urlsSection.Simple.Name = "Contoso"
            urlsSection.Simple.Url = "http://www.contoso.com"
            urlsSection.Simple.Port = 8080

            config.Sections.Add(sectionName, urlsSection)
            urlsSection.SectionInformation.ForceSave = True
            config.Save(ConfigurationSaveMode.Full)
        End If
    Catch e As ConfigurationErrorsException
        Console.WriteLine("[CreateSection: {0}]", e.ToString())
    End Try

End Sub