I started to use Json.NET to convert a string in JSON format to object or viceversa. I am not sure in the Json.NET framework, is it possible to convert a string in JSON to XML format and viceversa?
Yes. Using the JsonConvert class which contains helper methods for this precise purpose:
// To convert an XML node contained in string xml into a JSON string
XmlDocument doc = new XmlDocument();
doc.LoadXml(xml);
string jsonText = JsonConvert.SerializeXmlNode(doc);
// To convert JSON text contained in string json into an XML node
XmlDocument doc = JsonConvert.DeserializeXmlNode(json);
Documentation here: Converting between JSON and XML with Json.NET