使用LINQ从Ienumerable创建JSON对象

Question

I am trying to use LINQ to JSON to create a JSON object using the http://james.newtonking.com/json (JSON.NET) framework.

Basically I am trying to create a certain structure from the IEnumerable output. Have something like Products-> Actual,forecast,Target.

The LINQ to XML statement works fine and I can see the result. Is it due to deferred execution and lazy evaluation in LINQ to XML? If yes, how do I solve it.

This is what my LINQ to XML method looks like

IEnumerable resultSet = (xmlDoc.Root.Descendants(ns + "Row").Select(result => new
        {
            MonthYearShortName = (DateTime)result.Element(ns + "Column0"),
            Product = (String)result.Element(ns + "Column1"),
            Actual = (decimal)result.Element(ns + "Column2"),
            Forecast = (decimal)result.Element(ns+"Column3"),
            Target = (decimal)result.Element(ns + "Column4"),
        }));

And this is my LINQ to JSON. The example I am using comes from http://james.newtonking.com/json/help/index.html?topic=html/CreatingLINQtoJSON.htm

JObject rss =
                resultSet.Select(p => new JObject(p.Product,
                    new JProperty("MonthYearShortName", p.MonthYearShortName),
                    new JProperty("Actual", p.Actual),
                    new JProperty("Forecast", p.Forecast),
                    new JProperty("Target", p.Target)));

            Console.WriteLine(rss.ToString());

When I execute the LINQ to JSON statements I get the below error message

Error   5   'System.Collections.IEnumerable' does not contain a definition for 'Select' and no extension method 'Select' accepting a first argument of type 'System.Collections.IEnumerable' could be found 

My usings

using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Xml.Linq;
using Extensions = System.Xml.Linq.Extensions;

Not really sure why I am unable to do a select in the second LINQ to JSON statement.

Any help would be great.

Thanks!

Answer 1

The Select extension method is defined on the generic IEnumerable<T> interface (not the non-generic IEnumerable ).

For the code to compile, you will need to first call Cast<>()

JObject rss =
         resultSet.Cast<XElement>().Select(p => new JObject(p.Product,
                    new JProperty("MonthYearShortName", p.MonthYearShortName),
                    new JProperty("Actual", p.Actual),
                    new JProperty("Forecast", p.Forecast),
                    new JProperty("Target", p.Target)));

            Console.WriteLine(rss.ToString());

(or convert to a generic IEnumerable<resultSet> in some other way)

Answer 2

This code should work if you are trying to get the JSON string:

 var resultSet = (xmlDoc.Root.Descendants("Row").Select(result => new
        {
            MonthYearShortName = (DateTime)result.Element(ns + "Column0"),
            Product = (String)result.Element("Column1"),
            Actual = (decimal)result.Element("Column2"),
            Forecast = (decimal)result.Element("Column3"),
            Target = (decimal)result.Element("Column4"),
        }));

 var json = JsonConvert.SerializeObject(resultSet);
 Console.WriteLine(json);