使用Json.Net反序列化嵌套的json对象返回null

Question

I am getting the following nested Json objects from an API I am calling.

{"status":"success","data":{"valid_for":3600,"token":"access_token","expires":1123123123123}}

The PostResponse class is like below

public class PostResponse
{
    public string status { get; set; }
    public Data data { get; set; }
}

public class Data
{
    public int valid_for { get; set; }
    public string token { get; set; }
    public int expires { get; set; }
}

I get null for postResponse with this code.

using (StreamReader reader = new StreamReader(resp.GetResponseStream()))
{
     Console.WriteLine(reader.ReadToEnd());
     postResponse = JsonConvert.DeserializeObject<PostResponse>(reader.ReadToEnd());
}

Answer 1

You need to reset your stream pointer position, since you already read from a stream when you used WriteLine method.

Stream stream = resp.GetResponseStream();
using (StreamReader reader = new StreamReader(stream))
{
    Console.WriteLine(reader.ReadToEnd());

    stream.Position = 0; //Reset position pointer
    reader.DiscardBufferedData();

    postResponse = JsonConvert.DeserializeObject<PostResponse>(reader.ReadToEnd());
}