WebApi GeoJson错误序列化数据

我有一个Web服务试图返回GeoJson数据，我一直收到这个错误

{“Message”：“发生错误 . ”，“ExceptionMessage”：“'ObjectContent`1'类型无法序列化内容类型'application / json; charset = utf-8'的响应正文 . ”，“ ExceptionType“：”System.InvalidOperationException“，”StackTrace“：null，”InnerException“：{”Message“：”发生错误 . “，”ExceptionMessage“：”方法或操作未实现 . “，”ExceptionType“ ：“System.NotImplementedException”，“StackTrace”：“at GeoJSON.Net.Converters.GeometryConverter.WriteJson（JsonWriter writer，Object value，JsonSerializer serializer）\ r \ n在Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeConvertable（JsonWriter writer， JsonConverter转换器，Object值，JsonContract Contract ，JsonContainerContract collectionContract，JsonProperty containerProperty）\ r \ n在Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue（JsonWriter writer，Object value，JsonContract valueContract，JsonProperty成员，JsonContainerContract containerContract，JsonProperty） containerProperty）\ r \ n at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeObject（JsonWriter writer，Object value，JsonObjectContract contract，JsonProperty member，JsonContainerContract collectionContract，JsonProperty containerProperty）\ r \ n在Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue（ JsonWriter writer，Object value，JsonContract valueContract，JsonProperty member，JsonContainerContract containerContract，JsonProperty containerProperty）\ r \ n在Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeList（JsonWriter writer，IEnumerable values，JsonArrayContract contract，JsonProperty member，JsonContainerContract collectionContract，JsonProperty containerProperty） ）\ r \ n在Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue（JsonWriter writer，Object value，JsonContract valueContract，JsonProperty成员，JsonContainerContract containerContract，JsonProperty containerProperty）\ r \ n在Newtonsoft.Json.Seria在Newtonsoft.Json.JsonSerializer.Serialize中，在Newtonsoft.Json.JsonSerializer.SerializeInternal（JsonWriter jsonWriter，Object value，Type objectType）\ r \ n的lization.JsonSerializerInternalWriter.Serialize（JsonWriter jsonWriter，Object value，Type objectType）\ r \ n JsonWriter jsonWriter，Object value）\ r \ n在System.Net.Http.Formatting.BaseJsonMediaTypeFormatter.WriteToStream（Type type，Object value，Stream writeStream，Encoding effectiveEncoding）\ r \ n在System.Net.Http.Formatting.JsonMediaTypeFormatter . WriteToStream（Type type，Object value，Stream writeStream，Encoding effectiveEncoding）\ r \ n在System.Net.Http.Formatting.BaseJsonMediaTypeFormatter.WriteToStream（Type type，Object value，Stream writeStream，HttpContent content）\ r \ n在System . Net.Http.Formatting.BaseJsonMediaTypeFormatter.WriteToStreamAsync（Type type，Object value，Stream writeStream，HttpContent content，TransportContext transportContext，CancellationToken cancellationToken）\ r \ n ---从前一个位置开始的堆栈跟踪异常被抛出--- \ r \ n在System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务任务）\ r \ n在System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification（任务任务）\ r \ n在System . System.Web.Http.WebHost.HttpControllerHandler.d__14.MoveNext（）“}}中的Runtime.CompilerServices.TaskAwaiter.GetResult（）\ r \ n

这是我的控制器

// POST api/geo
    public List<GeoJSON.Net.Feature.Feature> Post([FromBody] locationsClass loc)
    {

        var lat = loc.lat;
        var lon = loc.lon;
        Geo Geo = new Geo();
        return Geo.GetRndNearybyLocationList(lat, lon, 400); 
    }

这是方法GetRndNearybyLocationList

public List<GeoJSON.Net.Feature.Feature> GetRndNearybyLocationList(double lat, double lon, int meters)
    {
        LocationObject thisRndLocation = new LocationObject();
        List<LocationObject> locationsList = new List<LocationObject>();

        //List<GeoJSON.Net.Geometry.GeographicPosition> Positions = new List<GeoJSON.Net.Geometry.GeographicPosition>();

        Random rnd = new Random();
        int dice = rnd.Next(1, 7);
        List<GeoJSON.Net.Feature.Feature> featureList = new List<GeoJSON.Net.Feature.Feature>();
        for (int i = 1; i <= dice; i++)
        {
            thisRndLocation = getLocation(lat, lon, meters);

            GeoJSON.Net.Geometry.GeographicPosition latlon = new GeoJSON.Net.Geometry.GeographicPosition(thisRndLocation.lat, thisRndLocation.lon, 0);
            GeoJSON.Net.Geometry.Point point = new GeoJSON.Net.Geometry.Point(latlon);
            Dictionary<string, object> properties = new Dictionary<string, object>();
            properties.Add("Color", "Blue");
            GeoJSON.Net.Feature.Feature feature = new GeoJSON.Net.Feature.Feature(point, properties);
            feature.Id = "FeatureId: " + i;
            featureList.Add(feature);

            //var coOrdinates = new GeoJSON.Net.Geometry.GeographicPosition(thisRndLocation.lat, thisRndLocation.lon);
            //Positions.Add(coOrdinates);
            //locationsList.Add(thisRndLocation);
            //var x = locationsList;

        }
        return featureList;
    }

在提琴手中我得到了错误，这是我的Ajax

$.ajax({
            type: 'Post',
            contentType: "application/json; charset=utf-8",
            url: 'http://localhost:8506/api/' + 'Geo' + '/?alloworigin=true',
            data: JSON.stringify({ lat: lat, lon: lon }),
            dataType: 'json',
            success: function (data) {
                for (var i = 0; i < data.length; i++) {
                    var obj = data[i];
                    console.log(obj.id);
                }
            },
            error: function (msg) {
                alert(msg.responsetext);
            }
        });

我尝试过的东西将newtonsoft升级到版本6

将此行添加到application_start

GlobalConfiguration.Configuration.Formatters.JsonFormatter.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore;

在WebApi配置的Register方法中覆盖：

var json = config.Formatters.JsonFormatter;
    json.SerializerSettings.PreserveReferencesHandling = Newtonsoft.Json.PreserveReferencesHandling.Objects;
    config.Formatters.Remove(config.Formatters.XmlFormatter);

到目前为止没有任何好处，任何想法？ ， 谢谢

这是固定类，确保您使用正确的基础GeoJSon

namespace GeoJSON.Net.Geometry
{
using System;
using System.Collections.Generic;
using Newtonsoft.Json;



/// <summary>
/// In geography, a point refers to a Position on a map, expressed in latitude and longitude.
/// </summary>
/// <seealso cref="http://geojson.org/geojson-spec.html#point"/>
public class Point : GeoJSONObject, IGeometryObject
{

    /// <summary>
    /// Initializes a new instance of the <see cref="Point"/> class.
    /// </summary>
    /// <param name="coordinates">The Position.</param>
    public Point(GeoJSON.Net.Geometry.GeographicPosition coordinates)
    {
        if (coordinates == null)
        {
            throw new ArgumentNullException("coordinates");
        }

        this.Coordinates = new List<GeoJSON.Net.Geometry.GeographicPosition> { coordinates };
        this.Type = GeoJSONObjectType.Point;
    }


    /// <summary>
    /// Initializes a new instance of the <see cref="Point"/> class.
    /// </summary>
    /// <param name="coordinates">The Position.</param>
    public Point(List<GeoJSON.Net.Geometry.GeographicPosition> coordinates)
    {
        if (coordinates == null)
        {
            throw new ArgumentNullException("coordinates");
        }

        this.Coordinates = coordinates;
        this.Type = GeoJSONObjectType.Point;
    }

    /// <summary>
    /// Gets the Coordinate(s).
    /// </summary>
    /// <value>The Coordinates.</value>
    [JsonProperty(PropertyName = "coordinates", Required = Required.Always)]
    //[JsonConverter(typeof(PositionConverter))]
    public List<GeoJSON.Net.Geometry.GeographicPosition> Coordinates { get; private set; }
}

}