对PetaPoco实体和WebApi问题使用[可序列化]

Question

I am trying to use [Serializable] attribute with a PetaPoco Entity so it can be stored in a REDIS Cache.

Adding the [Serializable] attribute to the PetaPoca Entity class allows it to be cached with a REDIS Caching provider but then changes the way the WebAPI serializes the Entity to JSON which breaks.

Is there a way to specify how the WebAPI serializes the object to JSON?

Examples below, for specifics this is within the DAL2 for DNN and using the https://github.com/davidjrh/dnn.rediscachingprovider REDIS Caching Provider for DNN.

DNN DAL2 / PetaPoco Object:

[TableName("sbCurrencyRates")]
//setup the primary key for table
[PrimaryKey("CurrID", AutoIncrement = true)]
//configure caching using PetaPoco
[Cacheable("sbCurrencyRates", CacheItemPriority.Default, 20)]
//scope the objects to the ModuleId of a module on a page (or copy of a module on a page)

[Serializable]
public class CurrRateInfo
{
    public int CurrID { get; set; }
    public string CurrCode { get; set; }
    public double CurrRate { get; set; }
    public DateTime LastUpdate { get; set; }
}

WebApi Controller:

public class RatesController : DnnApiController
{
    [AllowAnonymous]
    [HttpGet]
    public HttpResponseMessage GetRates()
    {
        CurrRatesController crc = new CurrRatesController();
        return Request.CreateResponse(HttpStatusCode.OK, crc.Get());
    }        
}

Thanks in advance.

Answer 1

Assuming you are using a fairly recent version of asp.net-web-api , then the Json.NET serializer is being used to serialize your class . By default Json.NET ignores [Serializable] , however it is possible to force it to serialize types with this attribute in the same way that BinaryFormatter does (ie by serializing their public and private fields ) by setting IgnoreSerializableAttribute on DefaultContractResolver to false . And in fact, asp.net does just this, which globally changes how [Serializable] classes are converted to JSON -- as you are seeing.

To prevent this, your options include the following:

1. Set IgnoreSerializableAttribute = true globally in asp.net. To do this see ASP.NET Web API and [Serializable] class or Setting IgnoreSerializableAttribute Globally in Json.net .

2. Mark your class with [JsonObject(MemberSerialization = MemberSerialization.OptOut)] :

    [Serializable] [JsonObject(MemberSerialization = MemberSerialization.OptOut)] public class CurrRateInfo { } 

3. Annotate your class with [DataContract] and [DataMember] attributes. These take precedence over [Serializable] .

    [Serializable] [DataContract] public class CurrRateInfo { [DataMember] public int CurrID { get; set; } [DataMember] public string CurrCode { get; set; } [DataMember] public double CurrRate { get; set; } [DataMember] public DateTime LastUpdate { get; set; } } 

   Do this if you don't want a direct dependency on Json.NET from your models, and don't want to change the global behavior of asp.net.