// ServiceExporter.cs lines 16-21
public static string ExportXml(ServiceDto service)
{
    var xml = new StringWriter();
    new System.Xml.Serialization.XmlSerializer(typeof(ServiceDto)).Serialize(xml, service);
    return xml.ToString();
}

// ServiceExporter.cs lines 38-46
public static string ExportJson(ServiceDto service)
{
    var json = JsonConvert.SerializeObject(service, Formatting.Indented,
        new JsonSerializerSettings
        {
            NullValueHandling = NullValueHandling.Ignore
        });
    return json.ToString(); // redundant .ToString()
}

public static string ExportXml(ServiceDto service)
{
    using var xml = new StringWriter();
    new System.Xml.Serialization.XmlSerializer(typeof(ServiceDto)).Serialize(xml, service);
    return xml.ToString();
}

public static string ExportJson(ServiceDto service)
{
    return JsonConvert.SerializeObject(service, Formatting.Indented,
        new JsonSerializerSettings
        {
            NullValueHandling = NullValueHandling.Ignore
        });
}