Pregunta

Estoy tratando de recorrer un archivo JSON y recuperar el título de cada registro de una API de Yahoo. ¿Alguien puede darme algunos consejos sobre cómo necesito hacer esto? Mi código es el siguiente:

   HttpWebRequest req = (HttpWebRequest)WebRequest.Create("http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20local.search%20where%20query%3D%22sushi%22%20and%20location%3D%22san%20francisco%2C%20ca%22&format=json&diagnostics=true&callback=cbfunc");
            HttpWebResponse rep = (HttpWebResponse)req.GetResponse();

            StreamReader sr = new StreamReader(rep.GetResponseStream());

            string data = sr.ReadToEnd();

            //Console.WriteLine(data); 

            var jss = new JavaScriptSerializer();
            var dict = jss.Deserialize<Dictionary<string,string>>(data);
¿Fue útil?

Solución

Podrías diseñar un par de clases para que coincidan con la estructura JSON devuelta por Yahoo. Tampoco uses el callback=cbfunc Parámetro porque de lo contrario Yahoo devuelve JSONP en lugar de JSON:

using System;
using System.Net;
using System.Web.Script.Serialization;

public class YahooResponse
{
    public Query Query { get; set; }
}

public class Query
{
    public Results Results { get; set; }
}

public class Results
{
    public Result[] Result { get; set; }
}

public class Result
{
    public string Title { get; set; }
}

class Program
{
    static void Main()
    {
        using (var client = new WebClient())
        {
            var json = client.DownloadString("http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20local.search%20where%20query%3D%22sushi%22%20and%20location%3D%22san%20francisco%2C%20ca%22&format=json&diagnostics=true")
            var jss = new JavaScriptSerializer();
            var result = jss.Deserialize<YahooResponse>(json);
            foreach (var item in result.Query.Results.Result)
            {
                Console.WriteLine(item.Title);
            }

        }
    }
}

Otros consejos

¿Necesita usar JSON para fines del lado del cliente? Si no, podría sugerir cambiar su formato de resultado a XML, formato = XML y usar LINQ a XML. Entonces podrías hacer esto:

if (tickers.Count() == 0)
            throw new InvalidOperationException("The list of tickers cannot be empty.");

        string url = BuildUrl(tickers);

        WebClient http = new WebClient();            
        string xml = http.DownloadString(url);

        List<Quote> quotes = new List<Quote>();

        XDocument doc = XDocument.Parse(xml);
        foreach (var el in doc.Descendants("quote"))
        {
            if (el.Name == "quote")
            {
                quotes.Add(new Quote()
                {
                    Symbol = el.Element("Symbol").Value,                        
                    TradeDate = el.Element("TradeDate").Value,
                    DaysLow = el.Element("DaysLow").IsEmpty ? null : (decimal?)el.Element("DaysLow"),
                    DaysHigh = el.Element("DaysHigh").IsEmpty ? null :(decimal?)el.Element("DaysHigh"),
                    YearLow = el.Element("YearLow").IsEmpty ? null : (decimal?)el.Element("YearLow"),
                    YearHigh = el.Element("YearHigh").IsEmpty ? null : (decimal?)el.Element("YearHigh"),
                    DividendShare = el.Element("DividendShare").IsEmpty ? null : (decimal?)el.Element("DividendShare"),
                    Open = el.Element("Open").IsEmpty ? null : (decimal?)el.Element("Open"),
                    PreviousClose = el.Element("PreviousClose").IsEmpty ? null : (decimal?)el.Element("PreviousClose"),
                    ShortRatio = el.Element("ShortRatio").IsEmpty ? null : (decimal?)el.Element("ShortRatio"),
                    OneyrTargetPrice = el.Element("OneyrTargetPrice").IsEmpty ? null : (decimal?)el.Element("OneyrTargetPrice"),
                    DividendYield = el.Element("DividendYield").IsEmpty ? null : (decimal?)el.Element("DividendYield"),
                    Ask = el.Element("Ask").IsEmpty ?  null : (decimal?)el.Element("Ask"),
                    Bid = el.Element("Bid").IsEmpty ? null : (decimal?)el.Element("Bid"),
                    AskRealtime = el.Element("AskRealtime").IsEmpty ? null : (decimal?)el.Element("AskRealtime"),
                    BidRealtime = el.Element("BidRealtime").IsEmpty ? null : (decimal?)el.Element("BidRealtime"),
                    BookValue = el.Element("BookValue").IsEmpty ? null : (decimal?)el.Element("BookValue"),                                
                    PercentChangeFromYearLow = el.Element("PercentChangeFromYearLow").Value,
                    LastTradeRealtimeWithTime = el.Element("LastTradeRealtimeWithTime").Value,
                    PercebtChangeFromYearHigh = el.Element("PercebtChangeFromYearHigh").Value,
                    LastTradeWithTime = el.Element("LastTradeWithTime").Value,
                    LastTradePriceOnly = el.Element("LastTradePriceOnly").Value,
                    Name = el.Element("Name").Value,
                    Notes = el.Element("Notes").Value,
                    LastTradeTime = el.Element("LastTradeTime").Value,
                    TickerTrend = el.Element("TickerTrend").Value,
                    StockExchange = el.Element("StockExchange").Value,
                    PercentChange = el.Element("PercentChange").Value,
                    AverageDailyVolume = (Int64?)el.Element("AverageDailyVolume"),
                    Change_PercentChange = el.Element("Change_PercentChange").Value,
                    Change = el.Element("Change").Value,
                    Commission = el.Element("Commission").Value,
                    ChangeRealtime = el.Element("ChangeRealtime").Value,
                    LastTradeDate = el.Element("LastTradeDate").Value
                });
            }
        }

        return quotes;
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