How to convert json array to a dictionary?

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I am trying to convert my json array into key/value pairs in a Dictionary but I keep getting my Keys and Values as null. Exception : System.ArgumentNullException: 'Value cannot be null.
Parameter name: key'

I am trying to get them as
"Key" : Value
"Key" : Value

Here is the Json

[
  {
    "id": 1,
    "name": "David",
    "type": 0
  },
  {
    "id": 12,
    "name": "John",
    "type": 0,
  }
]

What I have tried:

var value = JsonConvert.DeserializeObject<List<KeyValuePair<string, object>>>(jsonString).ToDictionary(x => x.Key, y => y.Value);

Posted 9-Jul-20 15:28pm

Member 14779968

Updated 9-Jul-20 20:18pm

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George Swan 10-Jul-20 1:33am

Can you please give an example of the key and the value that you want to get from your Json string? Do you want the 'id' as the key and the 'name' and 'type' as the value?

PIEBALDconsult 10-Jul-20 9:26am

Do you have an extraneous COMMA? "type": 0,

[no name] 14-Jul-20 13:22pm

Post the example of the output you expect. If you want a Dictionary then just deserialize it to it:
var res = JsonConvert.DeserializeObject<list<dictionary<string,object>>>(json);

You do have a dictionary but actually two of them since there are two objects in your collections, you can't just combine them since keys would be duplicated. You need to specify a key like e.g. id and then the value will be e.g an anonymous object with name and type. Depends what you real scenario is.

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George Swan · Answer 1 · 2020-07-09T20:18:00

Assuming you want id as the key and Person as the value, you can do something like this.

C#

 public class Person
  {
      public int id { get; set; }
      public string name { get; set; }
      public int type { get; set; }
  }

string jsonString = @"[
 {
  'id': 1,
  'name': 'David',
  'type': 0
 },
 {
  'id': 12,
  'name': 'John',
  'type': 0
 }
]";

 var dictionary = JsonConvert.DeserializeObject<IEnumerable<Person>>(jsonString).
                  Select(p => (Id: p.id, Record: p)).
                  ToDictionary(t => t.Id, t => t.Record);

Andre Oosthuizen · Answer 2 · 2020-07-09T16:31:00

It seems that no value is returned for a key, do a check if a value is empty, something like this might help -

C#

static void Main(String[] args) 
    {
        string number = Console.ReadLine();
        int n;
        Int32.TryParse(number, out n);

        var value = new Dictionary();

        for(int i = 0; i < n; i++)
        {
            //Try to use better naming conventions...
            string myKey = Console.ReadLine();
            string myValue = Console.ReadLine();
            value.Add(myKey, myValue);
        }

        foreach (var pair in value)
        {
            string myKey = pair.Key;
            string myValue = pair.Value;
        }


        string x = Console.ReadLine();
        if(x == null || !value.ContainsKey(x))
        {
            Console.WriteLine("Not Found");
        }
        else
        {
            string result = value[x];
            Console.Write(x);
            Console.Write("=");
            Console.Write(result);
        }
    }

How to convert json array to a dictionary?

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