Serializing custom exception object

Question

It's a .net core project running on a Mac. I've a custom Exception class that I'm serializing as JSON as output in case of an error.

  public class HttpException : Exception {
    private readonly int statusCode;

    public HttpException() {}

    public HttpException(int statusCode, string message) : base(message) {
        this.statusCode = statusCode;
    }

    public int StatusCode {get {return this.statusCode;}}
}

Code related to json serialization

Exception exception = (Exception)serviceRequest.ResultData;
MemoryStream memoryStream = new MemoryStream();  
DataContractJsonSerializer dataContractJsonSerializer = new DataContractJsonSerializer(typeof(Exception));  


// it fails here
dataContractJsonSerializer.WriteObject(memoryStream, exception);  


byte[] json = memoryStream.ToArray();  
memoryStream.Close();  
Console.WriteLine(Encoding.UTF8.GetString(json, 0, json.Length));

System.Runtime.Serialization.SerializationException: Type 'Service.Model.Exceptions.HttpException' with data contract name 'HttpException:http://schemas.datacontract.org/2004/07/Service.Model.Exceptions' is not expected. Add any types not known statically to the list of known types - for example, by using the KnownTypeAttribute attribute or by adding them to the list of known types passed to DataContractSerializer. at System.Runtime.Serialization.XmlObjectSerializerWriteContext.SerializeAndVerifyType(DataContract dataContract, XmlWriterDelegator xmlWriter, Object obj, Boolean verifyKnownType, RuntimeTypeHandle declaredTypeHandle, Type declaredType)

Edit

Trying to use System.Web.Extensions but have squiggly lines.

Matt it's not duplicate. The issue was with new DataContractJsonSerializer(typeof(HttpException));, I used Exception before. this brings another question, how can I make it generic because system can throw different kinds of exceptions, do I've to narrow down to typeof each? — App2015
Use Json.Net string json = JsonConvert.SerializeObject(exception); it will work — Eser
@Eser I wish but I can't fall outside with 3rd party libraries, only native implementations because of some requirements. — App2015

Eser Eser · Accepted Answer · 2018-03-13T21:31:37

I wish but I can't fall outside with 3rd party libraries, only native implementations because of some requirements.

You can include the System.Web.Extensions library and use JavaScriptSerializer

var ser = new JavaScriptSerializer();
string json = ser.Serialize(exception);

But as I said in comments, I would prefer Json.Net

Serializing custom exception object

2 Answers