Confused on how to create a Data Model Entity Framework-CodePudding

I am supposed to create a controller for the format below. I made the following data model and controller, but I am getting an error "Objects reference is not set to an instance of an object"

I am not very familiar with the framework and most sure what's wrong with the current implimentation

{
    "MacAddress": "30:a3:d5:a6:e4:b3",
    "TotalNodes": 1,
    "Report": [{
        "Status": [{
            "ID": 3,
            "Val": 0,
            "RSSI": {
                "Hop1": -80,
                "Hop2": -10
            },
            "Route": {
                "Id1": 3,
                "Id2": 9
            }
        }]
    }]
}

namespace Data.Models
{
    public class SensorsData
    {
        public string MacAddress { get; set; }
        public int TotalNodes { get; set; }
        public List<SensorReport> Report{ get; set; }

        public class SensorReport
        {
            public List<Status> Status { get; set; }
        }

        public class Status
        {
            public int ID { get; set; }
            public string Val { get; set; }
            public Nullable<int> HealthVal { get; set; }
            public List<sensorsRSSI> RSSI;
            public List<sensorsRoute> Route;

        }

        public class sensorsRSSI
        {
            public Nullable<int> Hop1 { get; set; }
            public Nullable<int> Hop2 { get; set; }

        }

        public class sensorsRoute
        {
            public Nullable<int> Id1 { get; set; }
            public Nullable<int> Id2 { get; set; }

        }
        public SensorsHealthData()
        {

        }
    }
}

and the controller looks like this

public IHttpActionResult Post(Data.Models.SensorsData sensorHealthData)
        {
            try
            {
                using (GSEntities dbContext = new GSEntities())
                {
                    var device= dbContext.devices.Where(c => c.MacAddress == SensorsData.HubMacAddress).FirstOrDefault();

                    foreach (SensorReport sensorReport in sensorData.HealthReport)
                    {

                        foreach (Status status in sensorReport.Status)
                        {
                            SensorsReport sensorReport = GSContext.SensorsReport.Add(new SensorsReport
                            {
                                Id = device.Id ,
                                TotalNodes = sensorData.TotalNodes,
                                ID = status.ID,
                                Val= status.Val,
                                Hop1 = status.RSSI.Hop1,
                                Hop2 = status.RSSI.Hop2,
                                Id1 = status.Route.Id1,
                                Id2 = status.Route.Id2
                            });
                        }
                    }

CodePudding user response：

Based on your model, the fault is the sensorsRSSI definition in the model class. It is not a list. It must be an object Also sensorsRoute must be an object.

Suggestion: If you are not similar to the framework or language you can use conversion tools like this for converting JSON to C# model classes.

    public class SensorData
    {
        public string MacAddress { get; set; }
        public int TotalNodes { get; set; }
        public List<Report> Report { get; set; }
    }

    public class Report
    {
        public List<Status> Status { get; set; }
    }

    public class sensorsRoute
    {
        public Nullable<int> Id1 { get; set; }
        public Nullable<int> Id2 { get; set; }
    }

    public class sensorsRSSI
    {
        public Nullable<int> Hop1 { get; set; }
        public Nullable<int> Hop2 { get; set; }
    }

    public class Status
    {
        public int ID { get; set; }
        public int Val { get; set; }
        public Nullable<int> HealthVal { get; set; }
        // Here is the fault
        // this property is not a list just a straight object
        public sensorsRSSI RSSI { get; set; }
        // And also this property must be an object.
        public sensorsRoute Route { get; set; }
    }