/// <summary>Search Yahoo Local</summary>
/// <see cref="http://developer.yahoo.com/geo/placefinder/"/>
public class GeocodeHelper
{
    private string YahooKey;
    public GeocodeHelper(string yahooKey)
    {
        this.YahooKey = yahooKey;
    }
 
    public async Task<ResultSet> Search(string query)
    {
        var _Url = "http://where.yahooapis.com/geocode?flags=j&";
        _Url += string.Format("appid={0}&", System.Uri.EscapeDataString(YahooKey.ToString()));
        _Url += string.Format("q={0}&", System.Uri.EscapeDataString(query));
        _Url = _Url.TrimEnd('&');
        string _JsonString = string.Empty;
        try
        {
            // fetch from rest service
            var _HttpClient = new System.Net.Http.HttpClient();
            var _HttpResponse = await _HttpClient.GetAsync(_Url);
            _JsonString = await _HttpResponse.Content.ReadAsStringAsync();
 
            // check for error
            if (_JsonString.Contains("{\"Error\":"))
                throw new InvalidResultException { JSON = _JsonString };
 
            // deserialize json to objects
            var _JsonBytes = Encoding.Unicode.GetBytes(_JsonString);
            using (MemoryStream _MemoryStream = new MemoryStream(_JsonBytes))
            {
                var _JsonSerializer = new DataContractJsonSerializer(typeof(RootObject));
                var _Result = (RootObject)_JsonSerializer.ReadObject(_MemoryStream);
                return _Result.ResultSet;
            }
        }
        catch (InvalidSomethingException) { throw; }
        catch (Exception e) { throw new InvalidSomethingException(e) { JSON = _JsonString }; }
    }
 
    public class InvalidSomethingException : Exception
    {
        public InvalidSomethingException() { }
        public InvalidSomethingException(Exception e) : base(string.Empty, e) { }
        public string JSON { get; set; }
    }
    public class InvalidCredentialsException : InvalidSomethingException { }
    public class InvalidResultException : InvalidSomethingException { }
 
    public class Result
    {
        public int quality { get; set; }
        public string latitude { get; set; }
        public string longitude { get; set; }
        public string offsetlat { get; set; }
        public string offsetlon { get; set; }
        public int radius { get; set; }
        public string name { get; set; }
        public string line1 { get; set; }
        public string line2 { get; set; }
        public string line3 { get; set; }
        public string line4 { get; set; }
        public string house { get; set; }
        public string street { get; set; }
        public string xstreet { get; set; }
        public string unittype { get; set; }
        public string unit { get; set; }
        public string postal { get; set; }
        public string neighborhood { get; set; }
        public string city { get; set; }
        public string county { get; set; }
        public string state { get; set; }
        public string country { get; set; }
        public string countrycode { get; set; }
        public string statecode { get; set; }
        public string countycode { get; set; }
        public string uzip { get; set; }
        public string hash { get; set; }
        public int woeid { get; set; }
        public int woetype { get; set; }
 
        // helpers
        public double Latitude { get { return double.Parse(this.latitude); } }
        public double Longitude { get { return double.Parse(this.longitude); } }
    }
 
    public class ResultSet
    {
        public string version { get; set; }
        public int Error { get; set; }
        public string ErrorMessage { get; set; }
        public string Locale { get; set; }
        public int Quality { get; set; }
        public int Found { get; set; }
        public List<Result> Results { get; set; }
    }
 
    public class RootObject
    {
        public ResultSet ResultSet { get; set; }
    }
}