c# - 将 JSON 字典反序列化为具有属性的对象

Question

我遇到了一个糟糕的 API，它返回以下 JSON:

{
   "root":[
      {
         "row":[
            {
               "name":"Foo",
               "value":"Some value"
            },
            {
               "name":"Bar",
               "value":"Some other value"
            }, (...)
         ]
      },
      {
         "row":[
            {
               "name":"Foo",
               "value":"Lorem"
            },
            {
               "name":"Bar",
               "value":"Ipsum"
            }, (...)
         ]
      }, (...)
   ]
}

我想使用 Newtonsoft.Json 将其反序列化为 C# 对象列表，这样名称将匹配对象属性，值将是属性值。该类看起来像这样:

class Row
{
    public string Foo { get; set; }
    public string Bar { get; set; }
    (...)
}

有什么想法吗？

Answer 1

您可以使用自定义 JsonConverter 来处理此问题。下面是一个简单的例子，它需要一些空检查等，但这是有道理的:

    public class RowConverter : JsonConverter
    {
        public override bool CanConvert(Type objectType)
        {
            return objectType == typeof(Row[]);
        }

        public override bool CanWrite => false;

        public override bool CanRead => true;

        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
        {

            if (reader.TokenType == JsonToken.Null)
            {
                return string.Empty;
            }
            else if (reader.TokenType == JsonToken.String)
            {
                return serializer.Deserialize(reader, objectType);
            }
            else
            {
                JObject obj = JObject.Load(reader);
                var root = obj["root"];
                if (root != null)
                {
                    var rows = new List<Row>();
                    foreach (var item in root)
                    {
                        var row = item["row"];
                        var newRow = new Row();
                        foreach(var field in row)
                        {
                            // better use reflection here to convert name-value to property setter
                            if (field.Value<string>("name") == "Foo")
                            {
                                newRow.Foo = field["value"].Value<string>();
                            }

                            if (field.Value<string>("name") == "Bar")
                            {
                                newRow.Bar = field["value"].Value<string>();
                            }
                        }

                        rows.Add(newRow);
                    }

                    return rows.ToArray();
                }
                return null;
            }
        }

        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
        {
            throw new NotImplementedException();
        }
    }

然后在你的 Row 类上:

[JsonConverter(typeof(RowConverter))]
public class Row
{
    public string Foo { get; set; }

    public string Bar { get; set; }
}

如果您需要将其包含在您的 MVC 中，请在 Startup.cs (asp.net core) 中:

services
    .AddMvc()
    .AddJsonOptions(options => { options.SerializerSettings.Converters.Add(new RowConverter()); });