反序列化时出错c＃

Question

我将我的json作为值传递给

var checkthis = JsonConvert.DeserializeObject(value);
string dothis = checkthis.ToString();
Activity   activity = new CompressedJsonActivityTransformer().Deserialize(dothis);

我需要关注我内置的CompressedJsonActivityTransformer，但我一直在活动活动中获得System.NullReferenceException。

我需要通过这个自定义反序列化器实现

public class CompressedJsonActivityTransformer:IActivitySerializer,IActivityDeserializer
{ 
    public CompressedJsonActivityTransformer();
    public Activity Deserialize(Stream stream);
    public Activity Deserialize(string jsonData);
    public void Serialize(Activity activity, Stream stream);
}

这是我从我的数据库中获取的动态对象，但需要解析它

{{
  "details": {
    "strength-workout": {
      "$type": "LTF.MyPlan.ActivityUtil.Model.Detail.WorkoutDetail, LTF.MyPlan.ActivityUtil",
      "type": "Workout",
      "workoutId": 94,
      "exerciseDetails": [
        {
          "type": "exercise",
          "exerciseID": 36,
          "sets": [
            {
              "reps": 20,
              "weight": 0,
              "isCompleted": false
            },
            {
              "reps": 20,
              "weight": 0,
              "isCompleted": false
            },
            {
              "reps": 20,
              "weight": 0,
              "isCompleted": false
            },
            {
              "reps": 20,
              "weight": 0,
              "isCompleted": false
            },
            {
              "reps": 20,
              "weight": 0,
              "isCompleted": false
            },
            {
              "reps": 20,
              "weight": 0,
              "isCompleted": false
            }
          ]
        },
        {
          "type": "exercise",
          "exerciseID": 46,
          "sets": [
            {
              "reps": 20,
              "weight": 4,
              "isCompleted": false
            },
            {
              "reps": 20,
              "weight": 4,
              "isCompleted": false
            },
            {
              "reps": 20,
              "weight": 4,
              "isCompleted": false
            },
            {
              "reps": 20,
              "weight": 4,
              "isCompleted": false
            },
            {
              "reps": 20,
              "weight": 4,
              "isCompleted": false
            },
            {
              "reps": 20,
              "weight": 4,
              "isCompleted": false
            }
          ]
        },
        {
          "type": "exercise",
          "exerciseID": 41,
          "sets": [
            {
              "reps": 20,
              "weight": 0,
              "isCompleted": false
            },
            {
              "reps": 20,
              "weight": 0,
              "isCompleted": false
            },
            {
              "reps": 20,
              "weight": 0,
              "isCompleted": false
            },
            {
              "reps": 20,
              "weight": 0,
              "isCompleted": false
            },
            {
              "reps": 20,
              "weight": 0,
              "isCompleted": false
            },
            {
              "reps": 20,
              "weight": 0,
              "isCompleted": false
            }
          ]
        },
        {
          "type": "exercise",
          "exerciseID": 39,
          "sets": [
            {
              "reps": 20,
              "weight": 0,
              "isCompleted": false
            },
            {
              "reps": 20,
              "weight": 0,
              "isCompleted": false
            },
            {
              "reps": 20,
              "weight": 0,
              "isCompleted": false
            },
            {
              "reps": 20,
              "weight": 0,
              "isCompleted": false
            },
            {
              "reps": 20,
              "weight": 0,
              "isCompleted": false
            },
            {
              "reps": 20,
              "weight": 0,
              "isCompleted": false
            }
          ]
        }
      ]
    }
  },
  "channels": {},
  "startTime": "2016-01-20T09:06:44.375836-06:00",
  "endTime": "2016-01-20T11:07:25.037335-06:00",
  "timerSeconds": 0,
  "performer": {
    "firstName": "Test",
    "nickname": "Test "
  }
}}