Dim connectionConfiguration As Configuration = Web.Configuration.WebConfigurationManager.OpenWebConfiguration("~")

        Dim csAddNewConString As New ConnectionStringSettings("key_nuova", "nuova connection string .......", "System.Data.SqlClient")

        Dim csNewConSection As ConnectionStringsSection = connectionConfiguration.ConnectionStrings

        csNewConSection.ConnectionStrings.Add(csAddNewConString)

        connectionConfiguration.Save(ConfigurationSaveMode.Modified)

        ConfigurationManager.RefreshSection("connectionStrings")