使用自定义Json序列化器创建集合

Question

这段代码是ASP.Net Web API控制器的一部分，在将其发送到UI之前，我有一个特殊的要求来修改最终Json中的某些值。

我当前的代码如下：

// Web API controller

public partial class ViewRController
        {
       [HttpGet]
            public DataMapList FetchEmployeeDataList()
            {
                DataMapList returnDataMapList = new DataMapList();

                return (returnDataMapList);
            }
        }

// Type definition and details

    [JsonObject]
        [JsonConverter(typeof(DataMapListSerializer))]
        public class DataMapList
        {
            public List<Dictionary<object, object>> employeeSalaryMappingList = null;

            public DataMapList()
            {
                employeeSalaryMappingList = new List<Dictionary<object, object>>();
                employeeSalaryMappingList.Add(new Dictionary<object, object>());

                employeeSalaryMappingList[0].Add(1, 10000);
                employeeSalaryMappingList[0].Add(2, 13000);
                employeeSalaryMappingList[0].Add(3, 15000);

                employeeSalaryMappingList.Add(new Dictionary<object, object>());

                employeeSalaryMappingList[1].Add(4, 9000);
                employeeSalaryMappingList[1].Add(5, 12000);
                employeeSalaryMappingList[1].Add(6, 11000);
            }
        }

// Custom Json serializer

public class DataMapListSerializer : JsonConverter
    {
        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
        {
            var employeeSalaryDataMapList = value as DataMapList;
            var employeeSalaryMappingList = employeeSalaryDataMapList.employeeSalaryMappingList;


            writer.WriteStartObject();
            foreach (var employeeSalaryMappingDictionary in employeeSalaryMappingList)
            {
                writer.WritePropertyName("ED");
                writer.WriteStartObject();

                foreach (var keyValuePair in employeeSalaryMappingDictionary)
                {
                    writer.WritePropertyName("ID-" + keyValuePair.Key);
                    serializer.Serialize(writer, keyValuePair.Value);
                }

                writer.WriteEndObject();
            }

            writer.WriteEndObject();
        }       

        public override bool CanConvert(Type objectType)
        {
            return typeof(DataMapList).IsAssignableFrom(objectType);
        }
    }

我面临的问题是我的结果：

{ 
   "ED": { "ID-1": 10000, "ID-2": 13000, "ID-3": 15000 }, 
  "ED": { "ID-4": 9000, "ID-5": 12000, "ID-6": 11000 } 
}

但是，由于我正在序列化一个集合（.Net列表类型，.Net集合），所以我希望得到以下结果

[ 
   "ED": { "ID-1": 10000, "ID-2": 13000, "ID-3": 15000 }, 
  "ED": { "ID-4": 9000, "ID-5": 12000, "ID-6": 11000 } 
]

实际上，当我尝试在Json Lint中进行验证时，当前结果显示了有效的Json但终止了一部分，因此将以下内容显示为有效的Json，但这仅是一种转移

{
    "ED": {
        "ID-4": 9000,
        "ID-5": 12000,
        "ID-6": 11000
    }
}

我试过替换writer.WriteStartObject(); 和writer.WriteEndObject(); 通过writer.WriteStartArray(); 和writer.WriteEndArray(); ，在遍历类型中的List的第一个foreach循环之前，但这会导致异常，因此无济于事

"exceptionMessage": "Token StartArray in state ObjectStart would result in an invalid JSON object. Path '

任何解决问题的建议请让我知道是否需要任何澄清

Answer 1

在JSON中 ，名称/值对必须位于对象{} ； 它们不能直接在数组[] 。 因此，您尝试创建的JSON无效，这就是为什么您遇到异常的原因：

[ 
   "ED": { "ID-1": 10000, "ID-2": 13000, "ID-3": 15000 }, 
   "ED": { "ID-4": 9000, "ID-5": 12000, "ID-6": 11000 } 
]

为了使其成为有效的集合，必须将每个ED名称/值对包装在这样的对象中：

[ 
   { 
      "ED": { "ID-1": 10000, "ID-2": 13000, "ID-3": 15000 } 
   }, 
   { 
      "ED": { "ID-4": 9000, "ID-5": 12000, "ID-6": 11000 } 
   }
]

一旦看到，解决方案就会变得清晰起来：在您的DataMapListSerializer您需要在循环外部使用DataMapListSerializer writer.WriteStartArray()和writer.WriteEndArray() ，并且需要在您的循环内部添加writer.WriteStartObject()和writer.WriteEndObject()环。

    writer.WriteStartArray();

    foreach (var employeeSalaryMappingDictionary in employeeSalaryMappingList)
    {
        writer.WriteStartObject();

            writer.WritePropertyName("ED");
            writer.WriteStartObject();

            foreach (var keyValuePair in employeeSalaryMappingDictionary)
            {
                writer.WritePropertyName("ID-" + keyValuePair.Key);
                serializer.Serialize(writer, keyValuePair.Value);
            }

            writer.WriteEndObject();

        writer.WriteEndObject();
    }

    writer.WriteEndArray();

小提琴： https : //dotnetfiddle.net/OT4HKM