c# - 如何在不知道格式的情况下反序列化 json？

Question

我使用 RestSharp 并且在反序列化 Json 时遇到问题。

如果成功，我会收到一个这样的 Json（数据是一个表）：

{"status": "OK", "data": "[...]"}

如果出现错误，我会收到一个 Json（数据是字符串）：

{"status": "ERROR", "data": "..."}

我怎么知道我是否必须用表格或字符串反序列化 Json？

我的方法是这样的（它返回一个表，但如果 Json 返回一个字符串作为数据会崩溃）：

public Task<Items> GetItemById(string id)
{
var client =
new RestClient(string.Format("{0}/{1}/{2}/{3}/{4}", _baseUrl, 
    AppResources.RestApiVersion, userId, token, AppResources.NotUse));

var tcs = new TaskCompletionSource<Items>();
var request = new RestRequest(string.Format("/items/get/{0}", id));
client.ExecuteAsync<Items>(request, response => {
    try
    {
        tcs.SetResult(new JsonDeserializer().Deserialize<Items>(response));
    }
    catch (InvalidCastException e)
    {

    }
});
return tcs.Task;
}

Answer 1

我使用此答案中的代码：将 JSON 反序列化为 C# 动态对象？

它根据 JSON 对象的内容生成一个动态对象。我非常喜欢它，尽管他的代码有几个我在下面的版本中修复的错误：

internal sealed class DynamicJsonConverter : JavaScriptConverter
{
    public override object Deserialize(IDictionary<string, object> dictionary, Type type, JavaScriptSerializer serializer)
    {
        if (dictionary == null)
            throw new ArgumentNullException("dictionary");

        return type == typeof(object) ? new DynamicJsonObject(dictionary) : null;
    }

    public override IDictionary<string, object> Serialize(object obj, JavaScriptSerializer serializer)
    {
        throw new NotImplementedException();
    }

    public override IEnumerable<Type> SupportedTypes
    {
        get { return new ReadOnlyCollection<Type>(new List<Type>(new[] { typeof(object) })); }
    }

    #region Nested type: DynamicJsonObject

    private sealed class DynamicJsonObject : DynamicObject
    {
        private readonly IDictionary<string, object> _dictionary;

        public DynamicJsonObject(IDictionary<string, object> dictionary)
        {
            if (dictionary == null)
                throw new ArgumentNullException("dictionary");
            _dictionary = dictionary;
        }

        public override string ToString()
        {
            var sb = new StringBuilder();
            ToString(sb);
            return sb.ToString();
        }

        private void ToString(StringBuilder sb)
        {
            sb.Append("{");
            var firstInDictionary = true;
            foreach (var pair in _dictionary)
            {
                if (!firstInDictionary)
                    sb.Append(",");
                firstInDictionary = false;
                var value = pair.Value;
                var name = pair.Key;
                if (value is string)
                {
                    sb.AppendFormat("\"{0}\":\"{1}\"", name, value);
                }
                else if (value is IDictionary<string, object>)
                {
                    sb.AppendFormat("\"{0}\":", name);
                    new DynamicJsonObject((IDictionary<string, object>)value).ToString(sb);
                }
                else if (value is ArrayList)
                {
                    sb.Append("\"");
                    sb.Append(name);
                    sb.Append("\":[");
                    var firstInArray = true;
                    foreach (var arrayValue in (ArrayList)value)
                    {
                        if (!firstInArray)
                            sb.Append(",");
                        firstInArray = false;
                        if (arrayValue is IDictionary<string, object>)
                            new DynamicJsonObject((IDictionary<string, object>)arrayValue).ToString(sb);
                        else if (arrayValue is string)
                            sb.AppendFormat("\"{0}\"", arrayValue);
                        else
                            sb.AppendFormat("{0}", arrayValue);

                    }
                    sb.Append("]");
                }
                else
                {
                    sb.AppendFormat("\"{0}\":{1}", name, value);
                }
            }
            sb.Append("}");
        }

        public override bool TryGetMember(GetMemberBinder binder, out object result)
        {
            if (!_dictionary.TryGetValue(binder.Name, out result))
            {
                // return null to avoid exception.  caller can check for null this way...
                result = null;
                return true;
            }

            var dictionary = result as IDictionary<string, object>;
            if (dictionary != null)
            {
                result = new DynamicJsonObject(dictionary);
                return true;
            }

            var arrayList = result as ArrayList;
            if (arrayList != null && arrayList.Count > 0)
            {
                if (arrayList[0] is IDictionary<string, object>)
                    result = new List<object>(arrayList.Cast<IDictionary<string, object>>().Select(x => new DynamicJsonObject(x)));
                else
                    result = new List<object>(arrayList.Cast<object>());
            }

            return true;
        }
    }

    #endregion
}

他的代码示例的其余部分都适用。