忽略 c# Custom Converter 上 jObject ReadJson 引发的异常

Question

我在尝试反序列化某些 json 时遇到了一些麻烦，因为它带有来自服务器的非转义双引号。由于我无权在服务器端修复此问题，因此我试图忽略有问题的 json。为此，我遵循了这些答案https://stackoverflow.com/a/21542099/2779990 和Ignore parsing errors during JSON.NET data parsing。当我使用errorArgs.ErrorContext.Handled = true; 时，响应对象是null。

所以我实现了自己的转换器：

public class FieldConverter : JsonConverter
    {
        public override bool CanConvert(Type objectType)
        {
            return objectType == typeof(FieldOperationDomain);
        }

        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
        {
            FieldDomain field = new FieldDomain();

            try
            {
                JObject jObject = JObject.Load(reader);

                JToken name = jObject["Name"];

                if (name.Type == JTokenType.String)
                {
                    field.Name = (string)name;
                }
                else
                {
                    field.Name = null;
                }

                JToken value = jObject["Value"];

                if (value.Type == JTokenType.String)
                {
                    field.Value = (string)value;
                }
                else
                {
                    field.Value = null;
                }

                return field;

            } catch (Exception e)
            {
                return new FieldDomain
                {
                    Name = "",
                    Value = ""
                };
            }
        }

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

我的 json 看起来像这样：

[
 {
   "id": "1d5c9ea3-7eb3-4fff-b8da-0a4dec891054",
   "RecordType": 1,
   "Field": []
 },
 {
   "id": "1d5c9ea3-7eb3-4fff-b8da-0a4dec891054",
   "RecordType": 1,
   "Field": [
      {
       "Name": "something",
       "Value": "Other something"
      },
      {
       "Name": "something",
       "Value": "Problematic "Other something""
      }
   ]
 }
]

我的域对象如下所示：

    public class MainDomain
    {
        [JsonProperty("id")]
        public long RecordType { get; set; }
        
        [JsonProperty("RecordType")]
        public long RecordType { get; set; }
        
        [JsonProperty("Fields")]
        public IEnumerable<Field> Fields { get; set; }
    }
    
    [JsonConverter(typeof(FieldOperationConverter))]
    public class FieldDomain
    {
        [JsonProperty("Name")]
        public string Name { get; set; }
        
        [JsonProperty("Value")]
        public string Value { get; set; }

        [OnError]
        internal void OnError(StreamingContext context, ErrorContext errorContext)
        {
            errorContext.Handled = true;
        }
    }

我什至还尝试将其添加到有问题的对象中：

        [OnError]
        internal void OnError(StreamingContext context, ErrorContext errorContext)
        {
            errorContext.Handled = true;
        }

问题是即使使用 try catch 块来捕获 JObject jObject = JObject.Load(reader); 上的任何异常，这也不能阻止 JsonConvert.DeserializeObject<IEnumerable<T>>(document, settings); 抛出异常。可以在ReadJson 方法中执行类似于errorArgs.ErrorContext.Handled = true; 的操作吗？

Answer 1

为什么不直接去掉双引号呢？ Json 很大吗？

private static string NormalizeJson(string json)
{
    
    var sb = new StringBuilder(json.Length);
    var jsonLength = json.Length;
    for (int i = 0; i < jsonLength; i++)
    {
        var ch = json[i];
        switch (ch)
        {
            case '"':
                // found quot
                sb.Append(ch);
                i++;
                var quIndex = GetEndIndex(json, i);

                var length = quIndex - i;
                 if (length > 0)
                {
                    // replace to white space
                    var buf = json.Substring(i, length)
                        .Replace("\"", " ");
                    sb.Append(buf);
                }

                sb.Append(json[quIndex]);
                i = quIndex;

                break;
            default:
                sb.Append(ch);
                break;
        }
    }

    return sb.ToString();
}

private static int GetEndIndex(string json, int i)
{
    var jsonLength = json.Length;
    var quIndex = i;
    //scan forward, try find end
    var isEnd = false;
    for (int j = i; j < jsonLength; j++)
    {
        var c = json[j];
        switch (c)
        {
            case '"':
                isEnd = !isEnd;
                quIndex = j;
                break;
            case ',':
            case ':':
            case '}':
            case ']':
                if (isEnd)
                    j = jsonLength;
                break;
            default:
                if (isEnd && !Char.IsWhiteSpace(c))
                    isEnd = false;
                break;
        }
    }

    return quIndex;
}