Analizar JSON en C#

Su clase de datos no coincide con el objeto JSON. Use esto en su lugar:

[DataContract]
public class GoogleSearchResults
{
    [DataMember]
    public ResponseData responseData { get; set; }
}

[DataContract]
public class ResponseData
{
    [DataMember]
    public IEnumerable<Results> results { get; set; }
}

[DataContract]
public class Results
{
    [DataMember]
    public string unescapedUrl { get; set; }

    [DataMember]
    public string url { get; set; }

    [DataMember]
    public string visibleUrl { get; set; }

    [DataMember]
    public string cacheUrl { get; set; }

    [DataMember]
    public string title { get; set; }

    [DataMember]
    public string titleNoFormatting { get; set; }

    [DataMember]
    public string content { get; set; }
}

Además, no es necesario crear instancias de la clase para obtener su tipo de deserialización:

public static T Deserialise<T>(string json)
{
    using (var ms = new MemoryStream(Encoding.Unicode.GetBytes(json)))
    {
        var serialiser = new DataContractJsonSerializer(typeof(T));
        return (T)serialiser.ReadObject(ms);
    }
}

Encontré este enfoque que analiza JSON en un objeto dinámico, extiende un DynamicObject y JavascriptConverter para convertir la cadena en un objeto.

DynamicJsonObject

public class DynamicJsonObject : DynamicObject
{
    private IDictionary<string, object> Dictionary { get; set; }

    public DynamicJsonObject(IDictionary<string, object> dictionary)
    {
        this.Dictionary = dictionary;
    }

    public override bool TryGetMember(GetMemberBinder binder, out object result)
    {
        result = this.Dictionary[binder.Name];

        if (result is IDictionary<string, object>)
        {
            result = new DynamicJsonObject(result as IDictionary<string, object>);
        }
        else if (result is ArrayList && (result as ArrayList) is IDictionary<string, object>)
        {
            result = new List<DynamicJsonObject>((result as ArrayList).ToArray().Select(x => new DynamicJsonObject(x as IDictionary<string, object>)));
        }
        else if (result is ArrayList)
        {
            result = new List<object>((result as ArrayList).ToArray());
        }

        return this.Dictionary.ContainsKey(binder.Name);
    }
}

Convertidor

public class DynamicJsonConverter : JavaScriptConverter
{
    public override object Deserialize(IDictionary<string, object> dictionary, Type type, JavaScriptSerializer serializer)
    {
        if (dictionary == null)
            throw new ArgumentNullException("dictionary");

        if (type == typeof(object))
        {
            return new DynamicJsonObject(dictionary);
        }

        return null;
    }

    public override IDictionary<string, object> Serialize(object obj, JavaScriptSerializer serializer)
    {
        throw new NotImplementedException();
    }

    public override IEnumerable<Type> SupportedTypes
    {
        get { return new ReadOnlyCollection<Type>(new List<Type>(new Type[] { typeof(object) })); }
    }
}

Uso ( json de muestra):

JavaScriptSerializer jss = new JavaScriptSerializer();
jss.RegisterConverters(new JavaScriptConverter[] { new DynamicJsonConverter() });

dynamic glossaryEntry = jss.Deserialize(json, typeof(object)) as dynamic;

Console.WriteLine("glossaryEntry.glossary.title: " + glossaryEntry.glossary.title);
Console.WriteLine("glossaryEntry.glossary.GlossDiv.title: " + glossaryEntry.glossary.GlossDiv.title);
Console.WriteLine("glossaryEntry.glossary.GlossDiv.GlossList.GlossEntry.ID: " + glossaryEntry.glossary.GlossDiv.GlossList.GlossEntry.ID);
Console.WriteLine("glossaryEntry.glossary.GlossDiv.GlossList.GlossEntry.GlossDef.para: " + glossaryEntry.glossary.GlossDiv.GlossList.GlossEntry.GlossDef.para);
foreach (var also in glossaryEntry.glossary.GlossDiv.GlossList.GlossEntry.GlossDef.GlossSeeAlso)
{
    Console.WriteLine("glossaryEntry.glossary.GlossDiv.GlossList.GlossEntry.GlossDef.GlossSeeAlso: " + also);
}

Este método tiene que devolver true, de lo contrario arrojará un error. Por ejemplo, puede lanzar un error si no existe una clave.

Devolver true y vaciar result devolverá un valor vacío en lugar de lanzar un error.

public override bool TryGetMember(GetMemberBinder binder, out object result)
{

    if (!this.Dictionary.ContainsKey(binder.Name))
    {
        result = "";
    }
    else
    {
        result = this.Dictionary[binder.Name];
    }

    if (result is IDictionary<string, object>)
    {
        result = new DynamicJsonObject(result as IDictionary<string, object>);
    }
    else if (result is ArrayList && (result as ArrayList) is IDictionary<string, object>)
    {
        result = new List<DynamicJsonObject>((result as ArrayList).ToArray().Select(x => new DynamicJsonObject(x as IDictionary<string, object>)));
    }
    else if (result is ArrayList)
    {
        result = new List<object>((result as ArrayList).ToArray());
    }

    return true; // this.Dictionary.ContainsKey(binder.Name);
}

Creo que todo el ejemplo sería útil. Este es el ejemplo de este problema.

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.ServiceModel.Web;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Json;
using System.IO;
using System.Text;
using System.Collections.Generic;

public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        GoogleSearchResults g1 = new GoogleSearchResults();
        const string json = @"{""responseData"": {""results"":[{""GsearchResultClass"":""GwebSearch"",""unescapedUrl"":""http://www.cheese.com/"",""url"":""http://www.cheese.com/"",""visibleUrl"":""www.cheese.com"",""cacheUrl"":""http://www.google.com/search?q\u003dcache:bkg1gwNt8u4J:www.cheese.com"",""title"":""\u003cb\u003eCHEESE\u003c/b\u003e.COM - All about \u003cb\u003echeese\u003c/b\u003e!."",""titleNoFormatting"":""CHEESE.COM - All about cheese!."",""content"":""\u003cb\u003eCheese\u003c/b\u003e - everything you want to know about it. Search \u003cb\u003echeese\u003c/b\u003e by name, by types   of milk, by textures and by countries.""},{""GsearchResultClass"":""GwebSearch"",""unescapedUrl"":""http://en.wikipedia.org/wiki/Cheese"",""url"":""http://en.wikipedia.org/wiki/Cheese"",""visibleUrl"":""en.wikipedia.org"",""cacheUrl"":""http://www.google.com/search?q\u003dcache:n9icdgMlCXIJ:en.wikipedia.org"",""title"":""\u003cb\u003eCheese\u003c/b\u003e - Wikipedia, the free encyclopedia"",""titleNoFormatting"":""Cheese - Wikipedia, the free encyclopedia"",""content"":""\u003cb\u003eCheese\u003c/b\u003e is a food consisting of proteins and fat from milk, usually the milk of   cows, buffalo, goats, or sheep. It is produced by coagulation of the milk \u003cb\u003e...\u003c/b\u003e""},{""GsearchResultClass"":""GwebSearch"",""unescapedUrl"":""http://www.ilovecheese.com/"",""url"":""http://www.ilovecheese.com/"",""visibleUrl"":""www.ilovecheese.com"",""cacheUrl"":""http://www.google.com/search?q\u003dcache:GBhRR8ytMhQJ:www.ilovecheese.com"",""title"":""I Love \u003cb\u003eCheese\u003c/b\u003e!, Homepage"",""titleNoFormatting"":""I Love Cheese!, Homepage"",""content"":""The American Dairy Association\u0026#39;s official site includes recipes and information   on nutrition and storage of \u003cb\u003echeese\u003c/b\u003e.""},{""GsearchResultClass"":""GwebSearch"",""unescapedUrl"":""http://www.gnome.org/projects/cheese/"",""url"":""http://www.gnome.org/projects/cheese/"",""visibleUrl"":""www.gnome.org"",""cacheUrl"":""http://www.google.com/search?q\u003dcache:jvfWnVcSFeQJ:www.gnome.org"",""title"":""\u003cb\u003eCheese\u003c/b\u003e"",""titleNoFormatting"":""Cheese"",""content"":""\u003cb\u003eCheese\u003c/b\u003e uses your webcam to take photos and videos, applies fancy special effects   and lets you share the fun with others. It was written as part of Google\u0026#39;s \u003cb\u003e...\u003c/b\u003e""}],""cursor"":{""pages"":[{""start"":""0"",""label"":1},{""start"":""4"",""label"":2},{""start"":""8"",""label"":3},{""start"":""12"",""label"":4},{""start"":""16"",""label"":5},{""start"":""20"",""label"":6},{""start"":""24"",""label"":7},{""start"":""28"",""label"":8}],""estimatedResultCount"":""14400000"",""currentPageIndex"":0,""moreResultsUrl"":""http://www.google.com/search?oe\u003dutf8\u0026ie\u003dutf8\u0026source\u003duds\u0026start\u003d0\u0026hl\u003den-GB\u0026q\u003dcheese""}}, ""responseDetails"": null, ""responseStatus"": 200}";
        g1 = JSONHelper.Deserialise<GoogleSearchResults>(json);

        foreach (Pages x in g1.responseData.cursor.pages)
        {
            // Anything you want to get
            Response.Write(x.label);

        }
    }
}

public class JSONHelper
{
    public static T Deserialise<T>(string json)
    {
        using (var ms = new MemoryStream(Encoding.Unicode.GetBytes(json)))
        {
            var serialiser = new DataContractJsonSerializer(typeof(T));
            return (T)serialiser.ReadObject(ms);
        }
    }

    public static string Serialize<T>(T obj)
    {
        DataContractJsonSerializer serializer = new DataContractJsonSerializer(obj.GetType());
        using (MemoryStream ms = new MemoryStream())
        {
            serializer.WriteObject(ms, obj);
            return Encoding.Default.GetString(ms.ToArray());
        }
    }
}

[DataContract]
public class GoogleSearchResults
{
    [DataMember]
    public ResponseData responseData { get; set; }

    [DataMember]
    public string responseStatus { get; set; }

}


public class ResponseData
{
    [DataMember]
    public Cursor cursor { get; set; }

    [DataMember]
    public IEnumerable<Results> results { get; set; }


}


[DataContract]
public class Cursor
{
    [DataMember]
    public IEnumerable<Pages> pages { get; set; }
}



[DataContract]
public class Pages
{
    [DataMember]
    public string start { get; set; }

    [DataMember]
    public string label { get; set; }

}


[DataContract]
public class Results
{
    [DataMember]
    public string unescapedUrl { get; set; }

    [DataMember]
    public string url { get; set; }

    [DataMember]
    public string visibleUrl { get; set; }

    [DataMember]
    public string cacheUrl { get; set; }

    [DataMember]
    public string title { get; set; }

    [DataMember]
    public string titleNoFormatting { get; set; }

    [DataMember]
    public string content { get; set; }
}

Traté de usar el código anterior, pero no funcionó. La estructura JSON devuelta por Google es muy diferente y hay un error muy importante en la función helper: una llamada a DataContractJsonSerializer.ReadObject() que en realidad deserializa los datos JSON en el objeto.

Aquí está el código que FUNCIONA en 2011:

using System;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Json;
using System.IO;
using System.Text;
using System.Collections.Generic;

namespace <YOUR_NAMESPACE>
{
    public class JSONHelper
    {
        public static T Deserialise<T>(string json)
        {
            T obj = Activator.CreateInstance<T>();
            MemoryStream ms = new MemoryStream(Encoding.Unicode.GetBytes(json));
            DataContractJsonSerializer serialiser = new DataContractJsonSerializer(obj.GetType());
            obj = (T)serialiser.ReadObject(ms);
            ms.Close();
            return obj;
        }
    }

    public class Result
    {
        public string GsearchResultClass { get; set; }
        public string unescapedUrl { get; set; }
        public string url { get; set; }
        public string visibleUrl { get; set; }
        public string cacheUrl { get; set; }
        public string title { get; set; }
        public string titleNoFormatting { get; set; }
        public string content { get; set; }
    }

    public class Page
    {
        public string start { get; set; }
        public int label { get; set; }
    }

    public class Cursor
    {
        public string resultCount { get; set; }
        public Page[] pages { get; set; }
        public string estimatedResultCount { get; set; }
        public int currentPageIndex { get; set; }
        public string moreResultsUrl { get; set; }
        public string searchResultTime { get; set; }
    }

    public class ResponseData
    {
        public Result[] results { get; set; }
        public Cursor cursor { get; set; }
    }

    public class GoogleSearchResults
    {
        public ResponseData responseData { get; set; }
        public object responseDetails { get; set; }
        public int responseStatus { get; set; }
    }
}

Para obtener el contenido del primer resultado, haga:

GoogleSearchResults googleResults = new GoogleSearchResults();
googleResults = JSONHelper.Deserialise<GoogleSearchResults>(jsonData);
string contentOfFirstResult = googleResults.responseData.results[0].content;

Gracias a todos por su ayuda. Esta es mi versión final, y funciona gracias a su ayuda combinada ! Solo estoy mostrando los cambios que hice, todo el resto está tomado de el trabajo de Joe Chung

public class GoogleSearchResults
    {
        [DataMember]
        public ResponseData responseData { get; set; }

        [DataMember]
        public string responseDetails { get; set; }

        [DataMember]
        public int responseStatus { get; set; }
    }

Y

 [DataContract]
    public class ResponseData
    {
        [DataMember]
        public List<Results> results { get; set; }
    }

Google Map API request and parse DirectionsResponse con C#, cambie el json en su url a xml y utilice el siguiente código para convertir el resultado en un objeto de Lista Genérica C# utilizable.

Me llevó un tiempo hacerlo. Pero aquí está

var url = String.Format("http://maps.googleapis.com/maps/api/directions/xml?...");
var result = new System.Net.WebClient().DownloadString(url);
var doc = XDocument.Load(new StringReader(result));

var DirectionsResponse = doc.Elements("DirectionsResponse").Select(l => new
{
    Status = l.Elements("status").Select(q => q.Value).FirstOrDefault(),
    Route = l.Descendants("route").Select(n => new
    {
        Summary = n.Elements("summary").Select(q => q.Value).FirstOrDefault(),
        Leg = n.Elements("leg").ToList().Select(o => new
        {
            Step = o.Elements("step").Select(p => new
            {
                Travel_Mode = p.Elements("travel_mode").Select(q => q.Value).FirstOrDefault(),
                Start_Location = p.Elements("start_location").Select(q => new
                {
                    Lat = q.Elements("lat").Select(r => r.Value).FirstOrDefault(),
                    Lng = q.Elements("lng").Select(r => r.Value).FirstOrDefault()
                }).FirstOrDefault(),
                End_Location = p.Elements("end_location").Select(q => new
                {
                    Lat = q.Elements("lat").Select(r => r.Value).FirstOrDefault(),
                    Lng = q.Elements("lng").Select(r => r.Value).FirstOrDefault()
                }).FirstOrDefault(),
                Polyline = p.Elements("polyline").Select(q => new
                {
                    Points = q.Elements("points").Select(r => r.Value).FirstOrDefault()
                }).FirstOrDefault(),
                Duration = p.Elements("duration").Select(q => new
                {
                    Value = q.Elements("value").Select(r => r.Value).FirstOrDefault(),
                    Text = q.Elements("text").Select(r => r.Value).FirstOrDefault(),
                }).FirstOrDefault(),
                Html_Instructions = p.Elements("html_instructions").Select(q => q.Value).FirstOrDefault(),
                Distance = p.Elements("distance").Select(q => new
                {
                    Value = q.Elements("value").Select(r => r.Value).FirstOrDefault(),
                    Text = q.Elements("text").Select(r => r.Value).FirstOrDefault(),
                }).FirstOrDefault()
            }).ToList(),
            Duration = o.Elements("duration").Select(p => new
            {
                Value = p.Elements("value").Select(q => q.Value).FirstOrDefault(),
                Text = p.Elements("text").Select(q => q.Value).FirstOrDefault()
            }).FirstOrDefault(),
            Distance = o.Elements("distance").Select(p => new
            {
                Value = p.Elements("value").Select(q => q.Value).FirstOrDefault(),
                Text = p.Elements("text").Select(q => q.Value).FirstOrDefault()
            }).FirstOrDefault(),
            Start_Location = o.Elements("start_location").Select(p => new
            {
                Lat = p.Elements("lat").Select(q => q.Value).FirstOrDefault(),
                Lng = p.Elements("lng").Select(q => q.Value).FirstOrDefault()
            }).FirstOrDefault(),
            End_Location = o.Elements("end_location").Select(p => new
            {
                Lat = p.Elements("lat").Select(q => q.Value).FirstOrDefault(),
                Lng = p.Elements("lng").Select(q => q.Value).FirstOrDefault()
            }).FirstOrDefault(),
            Start_Address = o.Elements("start_address").Select(q => q.Value).FirstOrDefault(),
            End_Address = o.Elements("end_address").Select(q => q.Value).FirstOrDefault()
        }).ToList(),
        Copyrights = n.Elements("copyrights").Select(q => q.Value).FirstOrDefault(),
        Overview_polyline = n.Elements("overview_polyline").Select(q => new
        {
            Points = q.Elements("points").Select(r => r.Value).FirstOrDefault()
        }).FirstOrDefault(),
        Waypoint_Index = n.Elements("waypoint_index").Select(o => o.Value).ToList(),
        Bounds = n.Elements("bounds").Select(q => new
        {
            SouthWest = q.Elements("southwest").Select(r => new
            {
                Lat = r.Elements("lat").Select(s => s.Value).FirstOrDefault(),
                Lng = r.Elements("lng").Select(s => s.Value).FirstOrDefault()
            }).FirstOrDefault(),
            NorthEast = q.Elements("northeast").Select(r => new
            {
                Lat = r.Elements("lat").Select(s => s.Value).FirstOrDefault(),
                Lng = r.Elements("lng").Select(s => s.Value).FirstOrDefault()
            }).FirstOrDefault(),
        }).FirstOrDefault()
    }).FirstOrDefault()
}).FirstOrDefault();

Espero que esto ayude a alguien.