Json.net fails when trying to deserialize a class that inherits from Exception

Question

I have a class SearchError that inherits from Exception, and when ever I try to deserialize it from a valid json I get the following exception:

ISerializable type 'SearchError' does not have a valid constructor. To correctly implement ISerializable a constructor that takes SerializationInfo and StreamingContext parameters should be present. Path '', line 1, position 81.

I tried implementing the suggested missing constructor, and it didn't help.

This is the class after implementing the suggested constructor:

public class APIError : Exception
{
    [JsonProperty("error")]
    public string Error { get; set; }

    [JsonProperty("@http_status_code")]
    public int HttpStatusCode { get; set; }

    [JsonProperty("warnings")]
    public List<string> Warnings { get; set; }

    public APIError(string error, int httpStatusCode, List<string> warnings) : base(error)
    {
        this.Error = error;
        this.HttpStatusCode = httpStatusCode;
        this.Warnings = warnings;
    }

    public APIError(System.Runtime.Serialization.SerializationInfo info, System.Runtime.Serialization.StreamingContext context)
        : base(info, context)
    {
        Error = (string)info.GetValue("error", typeof(string));
        HttpStatusCode = (int)info.GetValue("@http_status_code", typeof(int));
        Warnings = (List<string>)info.GetValue("warnings", typeof(List<string>));
    }
}

Now I'm getting the following exception (also in json.net code):

Member 'ClassName' was not found.

I also tried implementing the same solution as in this related question, also got the same error above.

This question has been answered here: stackoverflow.com/a/3423037/504836 — joelnet
– joelnet, Commented Aug 13, 2013 at 2:25

Community · Accepted Answer · 2017-05-23 11:48:28Z

15

This question has been answered here: https://stackoverflow.com/a/3423037/504836

Adding a new constructor

public Error(SerializationInfo info, StreamingContext context){}

solved my problem.

Here complete code:

[Serializable]
public class Error : Exception
{

    public string ErrorMessage { get; set; }

    public Error(SerializationInfo info, StreamingContext context) {
        if (info != null)
            this.ErrorMessage = info.GetString("ErrorMessage");
    }
    public override void GetObjectData(SerializationInfo info,StreamingContext context)
    {
        base.GetObjectData(info, context);

        if (info != null)
            info.AddValue("ErrorMessage", this.ErrorMessage);
    }
}

edited May 23, 2017 at 11:48

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answered Aug 13, 2013 at 2:28

joelnet

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3 Comments

Triynko Over a year ago

And this answer is useless, because you can't always just add a member to a class you don't own. For example, I have this error trying to serialize a DbUpdateConcurrencyException thrown by the Entity Framework. I have no control over that class or its members or what kind of instance is thrown.

David A. Gray Over a year ago

@Lukasz Lysik is correct that the answer needs improving, but the best improvement is, in fact, a simplification. I have confirmed by stepping through code and saving the entire object and its properties that the only statement that must be in GetObjectData is the first one, base.GetObjectData(info, context); I have confirmed that every property gets populated, including the HRESULT, which is protected in .NET 2.0. The same holds for the constructor, too.

Zapnologica Over a year ago

Is there any particular reason for this? Is it a bug in JSON.NET? This is a horrible thing to add to hundreds of custom exceptions.

competent_tech · Accepted Answer · 2013-01-06 19:55:35Z

5

As the error says, you are missing the serialization constructor:

public class SearchError : Exception
{
    public SearchError(System.Runtime.Serialization.SerializationInfo info, System.Runtime.Serialization.StreamingContext context) : base(info, context)
    {

    }
}

answered Jan 6, 2013 at 19:55

competent_tech

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5 Comments

Benjamin K. Over a year ago

I've tried your suggestion which I already tried before, and now I'm getting some other exception (see above).

joelnet Over a year ago

": base(info, context)" throws an Exception "Member 'ClassName' was not found."

competent_tech Over a year ago

@joelnet: that's a problem with your code, not the answer. See MSDN link for example: msdn.microsoft.com/en-us/library/…

competent_tech Over a year ago

@joelnet: the example in the answer is working. We have dozens of classes that are configured this way. In addition, the MSDN link contains a working example. If you are having a specific problem with your code, then you should create a new question rather than downvoting an answer and then asking for help in comments.

Triynko Over a year ago

The serialization constructor isn't always missing, it could be protected, such as with a DbUpdateConcurrencyException in the Entity Framework. Also, this kind of answer isn't good, because it can't be applied if you don't own the class. This seems more like a bug in JSON.NET at this point for it's inability to find a protected constructor.

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