MongoDb C# ObjectId序列化问题处理-11

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

        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
        {
            if (reader.TokenType != JsonToken.String)
            {
                throw new Exception(
                    String.Format("Unexpected token parsing ObjectId. Expected String, got {0}.",
                                  reader.TokenType));
            }

            var value = (string)reader.Value;
            return String.IsNullOrEmpty(value) ? ObjectId.Empty : new ObjectId(value);
        }

        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
        {
            if (value is ObjectId)
            {
                var objectId = (ObjectId)value;

                writer.WriteValue(objectId != ObjectId.Empty ? objectId.ToString() : String.Empty);
            }
            else
            {
                throw new Exception("Expected ObjectId value.");
            }
        }
    }

[JsonConverter(typeof(ObjectIdConverter))]
public string _id { get; set; }

[JsonIgnore]
public override  ObjectId _Id { get; set; }

[BsonIgnore]
public string _IdStr
{
     get
     {
          return Id.ToString();
     }
     set
     {
          ObjectId id;
          ObjectId.TryParse(value, out id);
          Id = id;
     }
}