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WinForms Error Cannot deserialize the current JSON array (e.g. [1,2,3]) into type

November 23, 2021

i have a code like this:

Dictionary<string, Diskop> data = JsonConvert.DeserializeObject<Dictionary<string, Diskop>>(res.Body.ToString());

and this is the Diskop class:

internal class Diskop : Dictionary<string, Diskop>
{
    public string isim { get; set; }
    public int no { get; set; }
    public int puan { get; set; }
}

and i get that error:

Newtonsoft.Json.JsonSerializationException: ‘Cannot deserialize the current JSON array (e.g. [1,2,3]) into type ‘System.Collections.Generic.Dictionary`2[System.String,Turuncu_Uygulama.Diskop]’ because the type requires a JSON object (e.g. {"name":"value"}) to deserialize correctly.

here is the json

[ {

"isim" : "AHMET UTKU GÖKSAL",
"no" : 929,
"puan" : 96
}, {
"isim" : "AHMET YASİR YILDIZ",
"no" : 969,
"puan" : 95
}, {
"isim" : "AKİF ENES ÖZDEMİR",
"no" : 953,
"puan" : 108
}, {
"isim" : "ALİ AKTÜRK",
"no" : 910,
"puan" : 111
}

>Solution :

Diskop should look like:

internal class Diskop
{
    [JsonProperty("isim")]
    public string Isim { get; set; }

    [JsonProperty("no")]
    public int No { get; set; }

    [JsonProperty("puan")]
    public int Puan { get; set; }
}

Deser should perhaps look like:

var data = JsonConvert.DeserializeObject<Diskop[]>(res.Body.ToString());

Or like:

var data = JsonConvert.DeserializeObject<List<Diskop>>(res.Body.ToString());

Because your json represents an array of Diskops:

[ 
{ "isim" : "AHMET UTKU GÖKSAL", "no" : 929, "puan" : 96 }, 
{ "isim" : "AHMET YASİR YILDIZ", "no" : 969, "puan" : 95 }, 
{ "isim" : "AKİF ENES ÖZDEMİR", "no" : 953, "puan" : 108 },
{ "isim" : "ALİ AKTÜRK", "no" : 910, "puan" : 111 }
]

You’d use a Dictionary<string, Diskop> if it looked like a mapping of diskops:

{ 
"a": { "isim" : "AHMET UTKU GÖKSAL", "no" : 929, "puan" : 96 }, 
"b": { "isim" : "AHMET YASİR YILDIZ", "no" : 969, "puan" : 95 }, 
"c": { "isim" : "AKİF ENES ÖZDEMİR", "no" : 953, "puan" : 108 },
"d": { "isim" : "ALİ AKTÜRK", "no" : 910, "puan" : 111 }
}