Convert querystring from/to object

A solution with Newtonsoft Json serializer and linq:

string responseString = "BaseNo=5&Width=100";
var dict = HttpUtility.ParseQueryString(responseString);
string json = JsonConvert.SerializeObject(dict.Cast<string>().ToDictionary(k => k, v => dict[v]));
StarBuildParams respObj = JsonConvert.DeserializeObject<StarBuildParams>(json);