c# - JSON 到数据表忽略数组

Question

我正在尝试编写一个通用方法，它将采用 JSON 字符串并将其转换为 DataTable(尽其所能)。

它工作正常，直到它遇到一个以数组作为属性之一的 JSON 对象。

我想做的是忽略数组属性并尽可能地进行转换。

我有一个 fiddle 示例来解释我正在尝试做的事情: https://dotnetfiddle.net/cgkNov

public static void Main()
{
    const string JsonObject = @"[{Id:""672af604-495b-4dc0-933e-6c55f56bef82"",""Name"":""1"",""MyArray"":[]}]";
    const string EndResultJsonObject = @"[{Id:""672af604-495b-4dc0-933e-6c55f56bef82"",""Name"":""1""}]";
    var settings = new JsonSerializerSettings
    {
        Error = (obj, args) =>
        {
            var context = args.ErrorContext;

            context.Handled = true;
        }
    };
    var a = JsonConvert.DeserializeObject<DataTable>(JsonObject, settings);

    Console.WriteLine(JsonConvert.SerializeObject(a));

    a = JsonConvert.DeserializeObject<DataTable>(EndResultJsonObject, settings);

    Console.WriteLine(JsonConvert.SerializeObject(a));
}

谢谢，亚历克斯

Answer 1

如果你想跳过数组，你可以使用这样的东西。这只是一个示例，您可能应该改进它。添加自定义转换器:

public class SkipArrayConverter : JsonConverter
{
    public override bool CanConvert(Type objectType)
    {
        return !objectType.IsArray;
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        JArray array = JArray.Load(reader);
        DataTable dataTable = new DataTable();
        int i = 0;
        foreach (JToken token in array.Children())
        {
            var dataRow = dataTable.NewRow();
            if (token.Type != JTokenType.Object) continue;

            if (i == 0)
            {
                SetColumns(dataTable, token);
                dataRow = dataTable.NewRow();
                i++;
            }

            foreach (JToken jToken in token)
            {
                if (((JProperty)jToken).Value.Type != JTokenType.Array)
                {
                    string name = ((JProperty)jToken).Name;
                    object value = ((JValue)((JProperty)jToken).Value).Value;
                    dataRow[name] = value;
                }
            }

            dataTable.Rows.Add(dataRow);
        }
        return dataTable;
    }

    private void SetColumns(DataTable dt, JToken token)
    {
        foreach (JToken jToken in token)
        {
            if (((JProperty)jToken).Value.Type != JTokenType.Array)
            {
                string name = ((JProperty)jToken).Name;
                object value = ((JValue)((JProperty)jToken).Value).Value;
                Type valueType = value.GetType();
                dt.Columns.Add(name, valueType);
            }
        }
    }

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

之后你就可以使用它了:

JsonSerializerSettings settings = new JsonSerializerSettings
{
    Converters = new List<JsonConverter> { new SkipArrayConverter() }
};
const string JsonObject = @"[{Id:""672af604-495b-4dc0-933e-6c55f56bef82"",Name:""1"",MyArray:[{}]}]";
const string EndResultJsonObject = @"[{Id:""672af604-495b-4dc0-933e-6c55f56bef82"",""Name"":""1""}]";
var a = JsonConvert.DeserializeObject<DataTable>(JsonObject, settings);

Console.WriteLine(JsonConvert.SerializeObject(a));

a = JsonConvert.DeserializeObject<DataTable>(EndResultJsonObject, settings);

Console.WriteLine(JsonConvert.SerializeObject(a));