Detecting a token with a json object using json.net

I'm using JSON.NET to de-serialize some JSON from a web service. I'm wanting to detect if a certain token is present and then act on that.

JToken token = JObject.Parse(JsonData);

I'm using the above to de-serialize t开发者_运维百科he data, i've then tried the following

if (((string)token.SelectToken("tokenname")) != null)
{
    Debug.WriteLine("found");
}
else
{
    Debug.WriteLine("not found");
}

each time it returns not found. Any idea's? thanks

---

I have been doing the following: (I'm assuming the JsonData is a string)

// data is a string variable
JObject obj = (JObject)JsonConvert.DeserializeObject(data);

if (obj != null) {
    if (obj["someProperty"] != null) {
        // perform logic here
    }
}

---

JObject obj=JObject.Parse(data);

JToken token;

if(obj.TryGetValue("tokenname", out token)) {
Debug.WriteLine(token);
}