Parse JSON to a Dictionary<string, List<string>>

Question

I have a JSON node similar to the following.

"folders":[
    {"Videos":[1196717,2874999,898084]},
    {"Fun":[2443301,3671]},
    {"News":[62689,58867,11385]}
]

I want to deserialize it into a Dictionary<string, List<int>> or something similar. I currently have the member:

[DataMember(Name = "folders")]
public Dictionary<string, List<int>> Folders;

And I expect an output like:

Folders = new Dictionary<string, List<int>>() {
    {"Videos", new List<int>() { 1196717, 2874999, 898084 }},
    {"Fun",    new List<int>() { 2443301, 3671 }},
    {"News",   new List<int>() { 62689, 58867, 11385 }}
};

I've implemented the deserializer as:

var serializer = new DataContractJsonSerializer(
    typeof(T),
    new DataContractJsonSerializerSettings() {
        DateTimeFormat = new DateTimeFormat("yyyy-MM-ddTHH:mm:ss.fffffffZ"),
    }
);
T result = (T)serializer.ReadObject(response);

But the just produces the error:

The data contract type 'System.Runtime.Serialization.KeyValue`2[[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[System.Collections.Generic.List`1[[System.Int32, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]], mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]' cannot be deserialized because the required data members 'Key, Value' were not found.

I understand this is because it is expecting something more like this, but the format is out of my control.

"folders":[
    {
        "key":"Videos",
        "value":[1196717,2874999,898084]
    },{
        "key":"Fun",
        "value":[2443301,3671]
    },{
        "key":"News",
        "value":[62689,58867,11385]
    }
]

What can I do to deserialize this?

Is there any impediment that prevents you from using JSON.NET? — Matías Fidemraizer
– Matías Fidemraizer, Commented Aug 25, 2013 at 7:46
I guess not. It appears to be available for Win 8 Apps. I'll investigate that. Any tips on how to accomplish this using JSON.NET? — Hand-E-Food
– Hand-E-Food, Commented Aug 25, 2013 at 8:10
Yes, haha, probably just using json.net your problem will be solved as is, that's the point. — Matías Fidemraizer
– Matías Fidemraizer, Commented Aug 25, 2013 at 17:16
@MatíasFidemraizer, JSON.NET on its own hasn't solved the issue. It complains that a Dictionary<TKey, TValue> doesn't implement ICollection<T>, and if I add the JsonArray attribute as suggested, then I end up with the same error as before. — Hand-E-Food
– Hand-E-Food, Commented Aug 26, 2013 at 7:11
Sadly I'm at work and I can't test that. Usually I deserialize objects using the ExpandoObjectConverter and I use a dynamic object. Why don't you try that? — Matías Fidemraizer
– Matías Fidemraizer, Commented Aug 26, 2013 at 10:11

Leszek P · Accepted Answer · 2016-04-01 11:18:41Z

1

Having: C#

public class wrap
{
    public List<Dictionary<string, List<string>>> folders { get; set; }
}

Json:

{"folders":[
    {"Videos":[1196717,2874999,898084]},
    {"Fun":[2443301,3671]},
    {"News":[62689,58867,11385]}
]
}

Using NewtonJson deserializer:

JsonDeserializer.Deserialize<wrap>(JsonInput)

I got successful object with List of 3 items of dictionaries.

Using DataContractJsonSerializer:

var serialzier = new DataContractJsonSerializer(typeof(wrap));
var stream = new MemoryStream(Encoding.UTF8.GetBytes(JsonInput));
Result = (wrap)serialzier.ReadObject(stream);

I got Unsuccessful object with List of 3 items of dictionaries, but they were empty. Maybe DataContractJsonSerializer needs some tweaking?

Hope it helps.

answered Apr 1, 2016 at 11:18

Leszek P

1,8661 gold badge18 silver badges24 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

jekcom · Accepted Answer · 2013-08-25 11:12:22Z

I used JavaScriptSerializer for this. Basically your json is actually a Dictionary<string, object>. I'm not sure why it would not let to do the casting to list, but any way, here are few simple lines which allows you to accomplish your task.

Note that i used this as jsonString (i.e without the "video:" part)

[
    {"Videos":[1196717,2874999,898084]},
    {"Fun":[2443301,3671]},
    {"News":[62689,58867,11385]}
]

If you want it with the video, then it is one more level of dictionary, i.e. Dictionary<string, Dictionary<string, object>> but works in same manner

Code:

    Dictionary<string, List<int>> result = new Dictionary<string, List<int>>();
    object[] desirializedJsonObject =(object[])new JavaScriptSerializer().DeserializeObject(jsonString);
    foreach (var obj in desirializedJsonObject)
    {
        // Get the record
        var firstRecord   = ((Dictionary<string, object>)obj).First();

        // Creat list of values
        var listOfValues = ((object[])firstRecord.Value).Select(x => Convert.ToInt32(x)).ToList();

        result.Add(firstRecord.Key, listOfValues);
    }

Divya · Accepted Answer · 2019-08-22 14:36:48Z

0

Use KeyValuePair class instead of dictionary,

List<KeyValuePair<string, List<string>>> uploadedfiles = JsonConvert.DeserializeObject<List<KeyValuePair<string, List<string>>>>(json)

answered Aug 22, 2019 at 14:36

Divya

3694 silver badges3 bronze badges

Collectives™ on Stack Overflow

Parse JSON to a Dictionary<string, List<string>>

3 Answers 3

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related