how to set the value of a json path using json.net

Question

I am trying to set an arbitrary path in a JSON structure and I am having difficulty figuring out how to do a simple set value...

What I would like is some method like, SetValue(path,value) which operates like SelectToken, but creates the path if it does not exist and sets the value.

public void SetPreference(string username, string path, string value)
{
    var prefs = GetPreferences(username);

    var jprefs = JObject.Parse(prefs ?? @"{}");

    var token = jprefs.SelectToken(path);

    if (token != null)
    {
        // how to set the value of the path?
    }
    else
       // how to add the path and value, example {"global.defaults.sort": { "true" }}
}

what I mean by global.defaults.sort path is actually { global: { defaults: { sort: { true } } } }

Answer 1

    public string SetPreference(string username, string path, string value)
    {
        if (!value.StartsWith("[") && !value.StartsWith("{"))
            value = string.Format("\"{0}\"", value);

        var val = JObject.Parse(string.Format("{{\"x\":{0}}}", value)).SelectToken("x");

        var prefs = GetPreferences(username);

        var jprefs = JObject.Parse(prefs ?? @"{}");

        var token = jprefs.SelectToken(path) as JValue;

        if (token == null)
        {
            dynamic jpart = jprefs;

            foreach (var part in path.Split('.'))
            {
                if (jpart[part] == null)
                    jpart.Add(new JProperty(part, new JObject()));

                jpart = jpart[part];
            }

            jpart.Replace(val);
        }
        else
            token.Replace(val);

        SetPreferences(username, jprefs.ToString());

        return jprefs.SelectToken(path).ToString();
    }