在 C# 中反序列化 JSON 对象

Question

My problem may be long to read, but I am sure the solution is quite simple for those who are familiar with the Visual Studio environment. I am quiet new and this isn't our field of studies, so we have some troubles. I will be glad to receive any help!

I have encountered the following problem:

I am trying to Deserialize the following JSON format:

[
    {
        "id": 1,
        "active": true,
        "air_drop_pos": {
            "latitude": 38.141833,
            "longitude": -76.425263
        },
        "fly_zones": [
            {
                "altitude_msl_max": 200.0,
                "altitude_msl_min": 100.0,
                "boundary_pts": [
                    {
                        "latitude": 38.142544,
                        "longitude": -76.434088,
                        "order": 1
                    },
                    {
                        "latitude": 38.141833,
                        "longitude": -76.425263,
                        "order": 2
                    },
                    {
                        "latitude": 38.144678,
                        "longitude": -76.427995,
                        "order": 3
                    }
                ]
            }
        ],
        "home_pos": {
            "latitude": 38.14792,
            "longitude": -76.427995
        },
        "mission_waypoints": [
            {
                "altitude_msl": 200.0,
                "latitude": 38.142544,
                "longitude": -76.434088,
                "order": 1
            }
        ],
        "off_axis_target_pos": {
            "latitude": 38.142544,
            "longitude": -76.434088
        },
        "emergent_last_known_pos": {
            "latitude": 38.145823,
            "longitude": -76.422396
        },
        "search_grid_points": [
            {
                "altitude_msl": 200.0,
                "latitude": 38.142544,
                "longitude": -76.434088,
                "order": 1
            }
        ]
    }
]

Using the command: Edit -> Paste Special -> Paste JSON as class I have created the required class to receive all the information.

Then in the C# I use the following code to deserialize the data:

using (webResponse3 = (HttpWebResponse)webRequest3.GetResponse()) 
{
     using (var stream = webResponse3.GetResponseStream())
     {
         using (var reader = new StreamReader(stream))
         {
           RootobjectMissions outObject1 = (RootobjectMissions)new JsonSerializer().Deserialize(reader, typeof(RootobjectMissions));
         }
     }
}

And I get the following error:

What is the possible way to change the format to the correct one? The source JSON looks to be an array which enters an array Class. What can be the problem?

I appreciate any help!

Answer 1

I do not know RootobjectMissions but i think the Deserialize needs string to work not stream reader so

Change this:

using (var reader = new StreamReader(stream))
     {
       RootobjectMissions outObject1 = (RootobjectMissions)new JsonSerializer().Deserialize(reader, typeof(RootobjectMissions));
     }

To this:

using (var reader = new StreamReader(stream))
     {
       RootobjectMissions outObject1 = (RootobjectMissions)new JsonSerializer().Deserialize(reader.ReadToEnd(), typeof(RootobjectMissions));
     }

Answer 2

I used json2csharp.com to create the sample classes. Deserialize the file contents as an array of 'Mission' instances:

    class Program
    {
        static void Main(string[] args)
        {
            using (var file = File.OpenRead("data.json"))
            {
                using (var reader = new StreamReader(file))
                {
                    var content = reader.ReadToEnd();
                    var missions = JsonConvert.DeserializeObject<Mission[]>(content);
                    System.Console.WriteLine(missions);
                }
            }
        }
    }

    public class AirDropPos
    {
        public double latitude { get; set; }
        public double longitude { get; set; }
    }

    public class BoundaryPt
    {
        public double latitude { get; set; }
        public double longitude { get; set; }
        public int order { get; set; }
    }

    public class FlyZone
    {
        public double altitude_msl_max { get; set; }
        public double altitude_msl_min { get; set; }
        public List<BoundaryPt> boundary_pts { get; set; }
    }

    public class HomePos
    {
        public double latitude { get; set; }
        public double longitude { get; set; }
    }

    public class MissionWaypoint
    {
        public double altitude_msl { get; set; }
        public double latitude { get; set; }
        public double longitude { get; set; }
        public int order { get; set; }
    }

    public class OffAxisTargetPos
    {
        public double latitude { get; set; }
        public double longitude { get; set; }
    }

    public class EmergentLastKnownPos
    {
        public double latitude { get; set; }
        public double longitude { get; set; }
    }

    public class SearchGridPoint
    {
        public double altitude_msl { get; set; }
        public double latitude { get; set; }
        public double longitude { get; set; }
        public int order { get; set; }
    }

    public class Mission
    {
        public int id { get; set; }
        public bool active { get; set; }
        public AirDropPos air_drop_pos { get; set; }
        public List<FlyZone> fly_zones { get; set; }
        public HomePos home_pos { get; set; }
        public List<MissionWaypoint> mission_waypoints { get; set; }
        public OffAxisTargetPos off_axis_target_pos { get; set; }
        public EmergentLastKnownPos emergent_last_known_pos { get; set; }
        public List<SearchGridPoint> search_grid_points { get; set; }
    }