C#でJSONをデシアライズできない(Newtonsoft.JSON)

Newtonsoft.Jsonを使ってJSONをデシアライズしようとしてますが、上手くできません。
ビルドはうまくいきますが、以下の例外エラーが出てしまいます。
JSONの読み込みは上手くできています。

**Newtonsoft.Json.JsonSerializationException:** 'Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'System.Collections.Generic.List`1[BEStatus.ShopItem]' 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<T>) 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 'error', line 1, position 9.'

JSONに変換する部分はこのように書きました。

C#
1using System;
2using System.Collections.Generic;
3using System.Diagnostics;
4using System.Text;
5using System.Net.Http;
6using Newtonsoft.Json;
7using System.Threading.Tasks;
8using System.Runtime.Serialization.Json;
9
10namespace BEStatus
11{
12    class GetApiData
13    {
14        //API情報
15        public string Token = "(Token key)";
16        public string Store_URL = "https://--";
17
18        //アイテムショップの処理 
19        public List<ShopItem> ShopList;
20        public async Task<List<ShopItem>> ShopItemAsync()
21        {
22            //List作成
23            ShopList = new List<ShopItem>();
24            HttpClient httpClient = new HttpClient();
25            httpClient.DefaultRequestHeaders.Add("Authorization", Token);
26            //非同期でAPI取得
27            Task<string> stringAsync = httpClient.GetStringAsync(Store_URL);
28            string result = await stringAsync;
29            Debug.WriteLine(result);
30            //Jsonに変換
31            ShopList = JsonConvert.DeserializeObject<List<ShopItem>>(result);
32            //Listでreturn
33            return ShopList;
34
35        }
36    }
37
38    
39    public class ShopImages
40    {
41        public string icon { get; set; }
42        public string background { get; set; }
43        public string featured { get; set; }
44        public string fbackground { get; set; }
45    }
46
47    public class ShopItem
48    {
49        public string name { get; set; }
50        public string rarity { get; set; }
51        public string type { get; set; }
52        public ShopImages images { get; set; }
53    }
54
55    public class ShopStore
56    {
57        public int cost { get; set; }
58        public int regularCost { get; set; }
59        public bool isFeatured { get; set; }
60        public bool isNew { get; set; }
61        public bool isCommunityVote { get; set; }
62    }
63
64    public class ShopDatum
65    {
66        public string itemId { get; set; }
67        public ShopItem item { get; set; }
68        public ShopStore store { get; set; }
69    }
70
71    public class ShopRootObject
72    {
73        public List<ShopDatum> data { get; set; }
74        public int updateAt { get; set; }
75    }  
76}

下のコードはリストを表示させるためのコードです(Xamarin)

C#
1using System;
2using System.Collections.Generic;
3using System.Net.Http;
4using Newtonsoft.Json;
5using System.Threading.Tasks;
6using System.Runtime.Serialization.Json;
7using System.Text;
8using Xamarin.Forms;
9using Xamarin.Forms.Xaml;
10
11namespace BEStatus
12{
13    [XamlCompilation(XamlCompilationOptions.Compile)]
14    public partial class TodayItemShop : ContentPage
15    {
16        
17        public ListView listView;
18        public List<ShopItem> ShopList;
19
20        public TodayItemShop()
21        {
22            //リストのデザイン系
23            InitializeComponent();
24
25            listView = new ListView
26            {
27                RowHeight = 60
28            };
29            Content = new StackLayout
30            {
31                VerticalOptions = LayoutOptions.FillAndExpand,
32                Children = { listView }
33            };
34
35            fetchArticles(new GetApiData());
36        }
37
38        //非同期でデータ取得
39        async void fetchArticles(GetApiData Api)
40        {
41            
42            ShopList = await Api.ShopItemAsync();
43            var items = new List<String>();
44            foreach (ShopItem value in ShopList)
45            {
46                items.Add(value.name);
47            }
48            listView.ItemsSource = items;
49        }
50    }
51}
52

読み込むJSONの文字列はこんな感じです。

JSON
1{
2  "data": [
3    {
4      "itemId": "ID",
5      "item": {
6        "name": "Sunrise",
7        "rarity": "rare",
8        "type": "glider",
9        "images": {
10          "icon": "URL",
11          "background": "URL",
12          "featured": "URL",
13          "fbackground": "URL"
14        }
15      },
16      "store": {
17        "cost": 800,
18        "regularCost": 800,
19        "isFeatured": true,
20        "isNew": false,
21        "isCommunityVote": false
22      }
23    },
24    {
25      "itemId": "ID",
26      "item": {
27        "name": "Sky Stripe",
28        "rarity": "uncommon",
29        "type": "glider",
30        "images": {
31          "icon": "URL",
32          "background": "URL",
33          "featured": "URL",
34          "fbackground": "URL"
35        }
36      },
37      "store": {
38        "cost": 500,
39        "regularCost": 500,
40        "isFeatured": true,
41        "isNew": false,
42        "isCommunityVote": false
43      }
44    },
45    {
46      "itemId": "ID",
47      "item": {
48        "name": "Axetec",
49        "rarity": "rare",
50        "type": "pickaxe",
51        "images": {
52          "icon": "URL",
53          "background": "URL",
54          "featured": "URL",
55          "fbackground": "URL"
56        }
57      },
58      "store": {
59        "cost": 800,
60        "regularCost": 800,
61        "isFeatured": true,
62        "isNew": false,
63        "isCommunityVote": false
64      }
65    },
66    {
67      "itemId": "ID",
68      "item": {
69        "name": "Stripe Slicer",
70        "rarity": "uncommon",
71        "type": "pickaxe",
72        "images": {
73          "icon": "URL",
74          "background": "URL",
75          "featured": "URL",
76          "fbackground": "URL"
77        }
78      },
79      "store": {
80        "cost": 500,
81        "regularCost": 500,
82        "isFeatured": true,
83        "isNew": false,
84        "isCommunityVote": false
85      }
86    },
87    {
88      "itemId": "ID",
89      "item": {
90        "name": "Iron Beak",
91        "rarity": "rare",
92        "type": "pickaxe",
93        "images": {
94          "icon": "URL",
95          "background": "URL",
96          "featured": "URL",
97          "fbackground": "URL"
98        }
99      },
100      "store": {
101        "cost": 800,
102        "regularCost": 800,
103        "isFeatured": true,
104        "isNew": false,
105        "isCommunityVote": false
106      }
107    
108    
109    }
110  ],
111  "updateAt": 1570406481
112}

JSONはあまり触ったことがないので初歩的な質問かもしれませんが、回答よろしくお願いします。

YAmaGNZ

2019/10/07 08:29 編集

ShopItemはどのように定義しているのですか？ JSON側もせめて１つのデータ分は記載できないのでしょうか？

CoreiNion

2019/10/07 09:42

修正しました。

行動規範の内容に同意します

回答2件

ベストアンサー

提示されているJSONをクラスとして定義したものがShopRootObjectクラス等でここまでは合っています。
ただ、デシリアライズする型がShopRootObjectクラスではなくList<ShopItem>としています。
この為、入力のJSONと型が合わずにエラーとなっています。

投稿2019/10/07 10:09

YAmaGNZ

総合スコア10469

resultに格納されるJSON文字列はShopRootObjectクラスの形式なので
ShopList = JsonConvert.DeserializeObject<List<ShopItem>>(result);
の部分を
ShopList = JsonConvert.DeserializeObject<ShopRootObject>(result);
に変更すれば通ると思います。

投稿2019/10/07 13:06