C# 將 JSON 文件反序列化為數組

Question

如何在 C# 中將 JSON 反序列化為數組，我想創建具有 JSON 屬性的圖像。 我當前的JSON 文件看起來像這樣......

{
  "test":[
    {
      "url":"150.png",
      "width":"300",
      "height":"300"
    },
    {
      "url":"150.png",
      "width":"300",
      "height":"300"
    },
    {
      "url":"150.png",
      "width":"300",
      "height":"300"
    }
  ]
}

我的 Form1 有一個 Picture1，我試圖用 Newtonsoft.json 反序列化，但我不知道如何將我的 JSON 對象反序列化為數組。 （我是開發初學者）

這是我當前的 Form1 代碼

using System;
using System.Windows.Forms;
using System.Collections.Generic;

using System.Globalization;
using Newtonsoft.Json;
using Newtonsoft.Json.Converters;
using System.IO;
using System.Linq;
using System.Drawing;

namespace viewer_mvc
{

    public partial class Index : Form
    {
        string url;
        int width, height;

        public Index()
        {
            InitializeComponent();
        }

        private void Index_Load(object sender, EventArgs e)
        {
            /*using (StreamReader file = File.OpenText("ultra_hardcore_secret_file.json"))
            {
                JsonSerializer serializer = new JsonSerializer();
                Elements img = (Elements)serializer.Deserialize(file, typeof(Elements));

                url = "../../Resources/" + img.url;
                width = img.width;
                height = img.height;
            }

            pictureBox1.Image = Image.FromFile(url);
            pictureBox1.Size = new Size(width, height);*/
            var json = File.ReadAllText("ultra_hardcore_secret_file.json");
            RootObject obj = JsonConvert.DeserializeObject<RootObject>(json);

            button1.Text = obj.test.ToString();

        }


        public class Elements
        {
            public string url { get; set; }
            public string width { get; set; }
            public string height { get; set; }
        }
        public class RootObject
        {
            public List<Elements> test { get; set; }
        }
    }
}

Answer 1

您可以嘗試使用JObject和JArray來解析 JSON 文件

using (StreamReader r = new StreamReader(filepath))
{
       string jsonstring = r.ReadToEnd();
       JObject obj = JObject.Parse(jsonstring);
       var jsonArray = JArray.Parse(obj["test"].ToString());

       //to get first value
       Console.WriteLine(jsonArray[0]["url"].ToString());

       //iterate all values in array
       foreach(var jToken in jsonArray)
       {
              Console.WriteLine(jToken["url"].ToString());
       }
}

Answer 2

您可以使用Newtoson Json.NET輕松反序列化此類文件

您可以創建兩個將由該框架自動反序列化的類。 例如。

        public class ListImage
        {
            public List<Image> test;
        }

        public class Image
        {
            public string url;
            public string width;
            public string height;
        }

        static void Main(string[] args)
        {
            var fileContent = File.ReadAllText("path to your file");
            var deserializedListImage = JsonConvert.DeserializeObject<ListImage>(fileContent);
        }

Answer 3

這對我有用。 我希望它也適用於你。

首先，我創建了一個類。

public class ImageInfo
{
    public string Url { get; set; }
    public string Width { get; set; }
    public string Height { get; set; }
}

而且，我做了這些事情。

  string json = 
             @"[{
                'url':'150.png',
                'width':'300',
                'height':'300'
              },
              {
                'url':'150.png',
                'width':'300',
                'height':'300'
              },
              {
                'url':'150.png',
                'width':'300',
                'height':'300'
              }]";

   var strImageInfo = JsonConvert.DeserializeObject<IEnumerable<ImageInfo>>(json);

Answer 4

我看到您正在反序列化為一個集合。 如果你想要一個數組，試試這樣的：

以下代碼使用您的示例 JSON 並輸出基於數組的輸出：

ImageResult.cs：

using System;
using System.Collections.Generic;

using System.Globalization;
using Newtonsoft.Json;
using Newtonsoft.Json.Converters;

namespace TestProject
{

    public partial class ImageResult
    {
        [JsonProperty("test", NullValueHandling = NullValueHandling.Ignore)]
        public Test[] Test { get; set; }
    }

    public partial class Test
    {
        [JsonProperty("url", NullValueHandling = NullValueHandling.Ignore)]
        public string Url { get; set; }

        [JsonProperty("width", NullValueHandling = NullValueHandling.Ignore)]
        [JsonConverter(typeof(ParseStringConverter))]
        public long? Width { get; set; }

        [JsonProperty("height", NullValueHandling = NullValueHandling.Ignore)]
        [JsonConverter(typeof(ParseStringConverter))]
        public long? Height { get; set; }
    }

    public partial class ImageResult
    {
        public static ImageResult FromJson(string json) => JsonConvert.DeserializeObject<ImageResult>(json, TestProject.Converter.Settings);
    }

    public static class Serialize
    {
        public static string ToJson(this ImageResult self) => JsonConvert.SerializeObject(self, TestProject.Converter.Settings);
    }

    internal static class Converter
    {
        public static readonly JsonSerializerSettings Settings = new JsonSerializerSettings
        {
            MetadataPropertyHandling = MetadataPropertyHandling.Ignore,
            DateParseHandling = DateParseHandling.None,
            Converters =
            {
                new IsoDateTimeConverter { DateTimeStyles = DateTimeStyles.AssumeUniversal }
            },
        };
    }

    internal class ParseStringConverter : JsonConverter
    {
        public override bool CanConvert(Type t) => t == typeof(long) || t == typeof(long?);

        public override object ReadJson(JsonReader reader, Type t, object existingValue, JsonSerializer serializer)
        {
            if (reader.TokenType == JsonToken.Null) return null;
            var value = serializer.Deserialize<string>(reader);
            long l;
            if (Int64.TryParse(value, out l))
            {
                return l;
            }
            throw new Exception("Cannot unmarshal type long");
        }

        public override void WriteJson(JsonWriter writer, object untypedValue, JsonSerializer serializer)
        {
            if (untypedValue == null)
            {
                serializer.Serialize(writer, null);
                return;
            }
            var value = (long)untypedValue;
            serializer.Serialize(writer, value.ToString());
            return;
        }

        public static readonly ParseStringConverter Singleton = new ParseStringConverter();
    }
}

使用代碼：

var json = File.ReadAllText("ultra_hardcore_secret_file.json");
ImageResult result = ImageResult().FromJson(json);