Problem in deserializing a JSON object in C#

Farhad Eft

Hi, When I try the following code, I receive an error which says:

Newtonsoft.Json.JsonSerializationException: 'Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'System.Collections.Generic.List`1[Test.Program+NewsItem]' because the type requires a JSON array (e.g. [1,2,3]) to deserialize correctly.

To fix this error either change the JSON to a JSON array (e.g. [1,2,3]) or change the deserialized type so that it is a normal .NET type (e.g. not a primitive type like integer, not a collection type like an array or List) that can be deserialized from a JSON object. JsonObjectAttribute can also be added to the type to force it to deserialize from a JSON object.

Path 'data', line 2, position 8.'

On this line:

List items = JsonConvert.DeserializeObject>(json);

Here is my Code:

using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text.RegularExpressions;
using System.Web.Script.Serialization;

namespace Test
{
public class Program
{
public class News
{

        public IList data { get; set; }
    }

    public class NewsItem
    {

        public IList title { get; set; }
        public IList body { get; set; }
    }

    public static void Main(string\[\] args)
    {
        string json = "";
        using (StreamReader r = new StreamReader("data3.json"))
        {
            json = r.ReadToEnd();
            List items = JsonConvert.DeserializeObject\>(json);
        }

        List  allNews = new System.Web.Script.Serialization.JavaScriptSerializer().Deserialize\>(json);

        foreach (var item in allNews)
        {

            foreach (var record in item.data)
            {
                Console.WriteLine(record.title);
                Console.WriteLine(record.body);
            }
            Console.ReadLine();
        }
    }
}

}

And here is my JSON sample object:

{
"data": [{
"body": ["

part 1-1

", "

part 1-2

"],
"link": "http://www.test.com",
"title": ["sample title 1"]
},
{
"body": ["

part 2-1

", "

part 2-2

"],
"link": "http://www.test.com",
"title": ["sample title 2"]
}
]
}

Thank you in advance for your time and considera

Dave Kreskowiak

Your data tag in the JSON is not an array yet your C# code it treating it as one.

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Dave Kreskowiak

Lost User

Your NewsItem class is missing a definition of the link JSON entry.

Richard Deeming

JSON.NET, and most other JSON libraries, will simply ignore any missing properties.

"These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

Richard Deeming

Farhad Eft wrote:

JsonConvert.DeserializeObject<List<NewsItem>>(json);

Farhad Eft wrote:

new System.Web.Script.Serialization.JavaScriptSerializer().Deserialize<List<News>>(json);

The JSON you've posted is neither a List<NewsItem> nor a List<News>; it is simply a single News object.

string json = File.ReadAllText("data3.json");
News allNews = JsonConvert.DeserializeObject<News>(json);
foreach (NewsItem item in allNews.data)
{
foreach (string title in item.title)
{
Console.WriteLine(title);
}

foreach (string body in item.body)
{
    Console.WriteLine(body);
}

Console.WriteLine();

}

"These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

Lost User

Thanks, something I need to test. However, looking at the question again, shouldn't it be trying to deserialise int a News class, rather than NewsItem?

Richard Deeming

Richard MacCutchan wrote:

shouldn't it be trying to deserialise int a News class, rather than NewsItem?

Indeed. As I posted below. :)

"These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

Farhad Eft

You guys are simply amazing!! Thank you! :)