Parsing a multidimensional JSON array with Newtonsoft Json.NET
I am returning Json like this:
[{"CreatedBy": "GIS_DB", "CreatedDate": "3/8/2012 10:44:00 AM" "Id": 39, "ModifiedBy": "," ModifiedDate ":", "Name": " CF-39 "," StatusId ": 1," TrailCoordinates ": [{" CreatedBy ":" GIS_DB "" CreatedDate ":" 3/8/2012 10:44:00 AM "," Id ": 1637," latitude ": +32.76004207," Longitude ": - +97.34006853," ModifiedBy ":", "ModifiedDate": "," SortOrder ": 1," TrailId ": 39}, {" CreatedBy ":" GIS_DB " , "CreatedDate": "3/8/2012 10:44:00 AM", "Id": 1638, "latitude": +32.76004333, "Longitude": - +97.34012121, "ModifiedBy": ", "ModifiedDate":"," SortOrder ": 2," TrailId ": 39}]}, {" CreatedBy ":" GIS_DB "," CreatedDate ":" 3/8/2012 10:44:00 AM "" Id ": 40," ModifiedBy ":", "ModifiedDate": "," Name ":" CF-40 "," StatusId ": 1," TrailCoordinates ": [{" CreatedBy ":" GIS_DB "" CreatedDate ":" 3/8/2012 10:44:00 AM "," Id ": 3755," latitude ": +32.76034332," Longitude ": - 97.3402069," ModifiedBy ":", "ModifiedDate": "," SortOrder ": 1, "TrailId": 40}, {"CreatedBy": "GIS_DB", "CreatedDate": "3/8/2012 10:44:00 AM", "ID": 3756, "latitude": +32,76019181, " longitude":- 97.3402448, "ModifiedBy": "," ModifiedDate ":", "SortOrder": 2, "TrailId": 40}]}]
These are my classes ...
public class Trails
{
[MonoTouch.Foundation.Preserve]
public Trails(){ TrailCoord = new List<trailcoords>();}
[MonoTouch.Foundation.Preserve, JsonProperty("Name")]
public string TrailName { get; set; }
[MonoTouch.Foundation.Preserve, JsonProperty("StatusId")]
public int StatusId { get; set; }
[MonoTouch.Foundation.Preserve, JsonProperty("TrailCoordinates")]
public List<trailcoords> TrailCoord { get; set; }
// public trailcoords
public Trails (string trailname, int statusid, List<trailcoords> trailcoord)
{
TrailName = trailname;
StatusId = statusid;
TrailCoord = trailcoord;
}
}
public class trailcoords
{
[MonoTouch.Foundation.Preserve]
public trailcoords(){}
[MonoTouch.Foundation.Preserve, JsonProperty("TrailId")]
public string TrailId { get; set; }
[MonoTouch.Foundation.Preserve, JsonProperty("Latitude")]
public double Latitude { get; set; }
[MonoTouch.Foundation.Preserve, JsonProperty("Longitude")]
public double Longitude { get; set; }
public trailcoords (string trailid, double latitude, double longitude)
{
TrailId = trailid;
Latitude = latitude;
Longitude = longitude;
}
}
List<Trails> Posts = JsonConvert.DeserializeObject<List<Trails>> ( json );
So, I'm not sure how to access the Latitude and Longitude items in my list. I can access things like TrailName without issue, but not sure what I am doing wrong with the array elements in the array. I would like to add them so that I can draw them as strings in a structure like the one I did (hardcoded values):
CLLocationCoordinate2D[] tmpTrail1 = new CLLocationCoordinate2D[]{
new CLLocationCoordinate2D(32.751531, -97.361755),
new CLLocationCoordinate2D(32.751451, -97.356625),
new CLLocationCoordinate2D(32.751500, -97.332077),
};
CLLocationCoordinate2D[] tmpTrail2 = new CLLocationCoordinate2D[] {
new CLLocationCoordinate2D(32.727353, -97.361139),
new CLLocationCoordinate2D(32.747731, -97.359896),
new CLLocationCoordinate2D(32.765735, -97.360360),
};
_trailOverlayPoints = new List<CLLocationCoordinate2D[]>();
_trailOverlayPoints.Add(tmpTrail1);
_trailOverlayPoints.Add(tmpTrail2);
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Instead of declaring a lot of classes, I will parse the json string like this
JArray jArr = (JArray)JsonConvert.DeserializeObject(jsonstr);
foreach (var item in jArr)
{
foreach(var subitem in item["TrailCoordinates"])
{
Console.WriteLine(subitem["Longitude"] + " " + subitem["Latitude"]);
}
}
If monotouch supports dynamic
you can also write
dynamic jArr2 = JsonConvert.DeserializeObject(jsonstr);
foreach (dynamic item in jArr2)
{
foreach (var subitem in item.TrailCoordinates)
{
Console.WriteLine(subitem.Longitude + " " + subitem.Latitude);
}
}
You can even use Linq
JArray jArr = (JArray)JsonConvert.DeserializeObject(jsonstr);
var coords = jArr
.Select(x => x["TrailCoordinates"])
.SelectMany(x=>x)
.Where(x => x["TrailId"].ToString() == "40")
.Select(x => new { Lat = double.Parse(x["Latitude"].ToString()), Lon=double.Parse(x["Longitude"].ToString()) })
.ToArray();
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