Json parsing F#

Question

Hello,

#r@"\.NETFramework\v4.0\Profile\Client\System.Runtime.Serialization.dll"
open System.Runtime.Serialization
open System.Runtime.Serialization.Json

[<DataContract>]
    type geo = {
        [<field: DataMember(Name = "type")>]
        t:string
        [<field: DataMember(Name = "coordinates")>]
        coordinates:string
        }


let decode (s:string)  = 
    let json = new DataContractJsonSerializer(typeof<geo>)
    let byteArray = Encoding.UTF8.GetBytes(s)
    let stream = new MemoryStream(byteArray)
    json.ReadObject(stream) :?> geo

let tw = {"type":"Point","coordinates":[-7.002648,110.449961]}

decode tw 

This returns -> End element 'coordinates' from namespace '' expected. Found element 'item' from namespace ''

How can I define the DataMember coordinates so that it understands ?

Thanks a lot

Answer 1

this works for me

#r "System.Runtime.Serialization"

open System.IO
open System.Text
open System.Runtime.Serialization
open System.Runtime.Serialization.Json

[<DataContract>]
    type geo = {
        [<field: DataMember(Name = "type")>]
        t:string
        [<field: DataMember(Name = "coordinates")>]
        coordinates:float[]
        }


let decode (s:string)  = 
    let json = new DataContractJsonSerializer(typeof<geo>)
    let byteArray = Encoding.UTF8.GetBytes(s)
    let stream = new MemoryStream(byteArray)
    json.ReadObject(stream) :?> geo

let tw = "{
    \"type\":\"Point\",
    \"coordinates\":[-7.002648,110.449961]
    }"

let v = decode tw // val v : geo = {t = "Point"; coordinates = [|-7.002648; 110.449961|];}