DataContractJsonSerializer - 在List <object>中反序列化DateTime

Question

我无法使用System.Runtime.Serialization.Json.DataContractJsonSerializer该类反序列化a中包含的DateTime实例List<object>.我似乎无法将DateTime反序列化为原始类型.将DataContractJsonSerializer始终反序列化到一个字符串类型的格式"/Date(1329159196126-0500)/".如果我通过使用强类型运行它,它将序列化和反序列化很好List<DateTime>,但是我正在寻找方法让串行器在简单列表或数组中遇到时识别并正确反序列化DateTimes object.

请注意,除了此列表将包含的基元和字符串之外,DateTimes是唯一的类型.这是我用来测试它的代码片段.

var list = new List<object> { 27, "foo bar", 12.34m, true, DateTime.Now };
var serializer = new DataContractJsonSerializer(typeof (List<object>));
using (MemoryStream ms = new MemoryStream())
{
    serializer.WriteObject(ms, list);
    ms.Position = 0;
    var deserializedList = serializer.ReadObject(ms) as List<object>;
}

Answer 1

在.NET Framework 4.5版中,它DataContractJsonSerializer有一个构造函数,它接受一个DataContractJsonSerializerSettings可用于设置的对象DateTimeFormat:

var ser = new DataContractJsonSerializer(typeof(CreateOmsEntryCommand),
              new DataContractJsonSerializerSettings
              {
                  DateTimeFormat = new DateTimeFormat("yyyy-MM-dd'T'HH:mm:ssZ")
              });

Answer 2

这似乎是非常奇怪的行为,我的猜测是它源于DateTime不是一个在JSON中被识别的类型.但是,您可以滚动自己的IDataContractSurrogate来修改序列化/反序列化过程.

要使用此功能,请在为此创建序列化程序时修改示例代码:

var serializer = new DataContractJsonSerializer(typeof(List<object>), null, int.MaxValue, false, new DateTimeDataContractSurrogate(), true);

然后添加这个类:

public class DateTimeDataContractSurrogate : IDataContractSurrogate
    {
        private static readonly Regex dateRegex = new Regex(@"/Date\((\d+)([-+])(\d+)\)/");
        private static readonly DateTime epoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);

        public object GetCustomDataToExport(Type clrType, Type dataContractType)
        {
            // not used
            return null;
        }

        public object GetCustomDataToExport(System.Reflection.MemberInfo memberInfo, Type dataContractType)
        {
            // not used
            return null;
        }

        public Type GetDataContractType(Type type)
        {
            // not used
            return type;
        }

        public object GetDeserializedObject(object obj, Type targetType)
        {
            // for debugging
            //Console.WriteLine("GetDeserializedObject: obj = {0} ({1}), targetType = {2}", obj, obj.GetType(), targetType);

            // only act on List<object> types
            if (obj.GetType() == typeof(List<object>))
            {
                var objList = (List<object>)obj;

                List<object> copyList = new List<object>(); // a list to copy values into. this will be the list returned.
                foreach (var item in objList)
                {
                    string s = item as string;
                    if (s != null)
                    {
                        // check if we match the DateTime format
                        Match match = dateRegex.Match(s);
                        if (match.Success)
                        {
                            // try to parse the string into a long. then create a datetime and convert to local time.
                            long msFromEpoch;
                            if (long.TryParse(match.Groups[1].Value, out msFromEpoch))
                            {
                                TimeSpan fromEpoch = TimeSpan.FromMilliseconds(msFromEpoch);
                                copyList.Add(TimeZoneInfo.ConvertTimeFromUtc(epoch.Add(fromEpoch), TimeZoneInfo.Local));
                                continue;
                            }
                        }
                    }

                    copyList.Add(item); // add unmodified
                }

                return copyList;
            }

            return obj;
        }

        public void GetKnownCustomDataTypes(System.Collections.ObjectModel.Collection<Type> customDataTypes)
        {
            // not used   
        }

        public object GetObjectToSerialize(object obj, Type targetType)
        {
            // for debugging
            //Console.WriteLine("GetObjectToSerialize: obj = {0} ({1}), targetType = {2}", obj, obj.GetType(), targetType);
            return obj;
        }

        public Type GetReferencedTypeOnImport(string typeName, string typeNamespace, object customData)
        {
            // not used
            return null;
        }

        public System.CodeDom.CodeTypeDeclaration ProcessImportedType(System.CodeDom.CodeTypeDeclaration typeDeclaration, System.CodeDom.CodeCompileUnit compileUnit)
        {
            // not used
            return typeDeclaration;
        }
    }

Answer 3

如果DataContractJsonSerializer不是必须的话,这里是使用Json.Net的解决方案.

var list = new List<object> { 27, "foo bar", 12.34m, true, DateTime.Now };

string json = JsonConvert.SerializeObject(list);
var orgObj=JsonConvert.DeserializeObject<List<object>>(json);

这是Json字符串

[27,"foo bar",12.34,true,"\/Date(1329161615596+0200)\/"]

和返回类型long,string,double,bool和DateTime