Bug 3811 - DataContractJsonSerializer deserialization fails with subclass of List<int> as known type
Summary: DataContractJsonSerializer deserialization fails with subclass of List<int> a...
Alias: None
Product: Class Libraries
Classification: Mono
Component: System ()
Version: 2.10.x
Hardware: PC Windows
: --- normal
Target Milestone: Untriaged
Assignee: Bugzilla
Depends on:
Reported: 2012-03-08 11:20 UTC by Rick Mohr
Modified: 2015-05-15 18:28 UTC (History)
2 users (show)

Is this bug a regression?: ---
Last known good build:

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Description Rick Mohr 2012-03-08 11:20:04 UTC
The following code runs correctly on .NET 4.0, but fails with Mono:

using System;
using System.Collections.Generic;
using System.IO;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Json;
using System.Text;

namespace MonoDeserializationFailure
    class Program
        static void Main(string[] args)
                var knownTypes = new List<Type> { typeof(IntList) };
                var serializer = new DataContractJsonSerializer(typeof(ListOfNumbers), knownTypes);

                string json = "{\"Numbers\": [85]}";
                using (var stream = new MemoryStream(UTF8Encoding.Default.GetBytes(json)))
                    var nums = (ListOfNumbers)serializer.ReadObject(stream);
                    Console.WriteLine("Success: " + nums.Numbers.Count);
            catch (Exception ex)
                Console.WriteLine("Failure: " + ex.Message);

    public class ListOfNumbers
        public IntList Numbers;

    public class IntList : List<int>
Comment 1 Miguel de Icaza [MSFT] 2015-05-15 18:24:41 UTC
This is fixed;   Test added as well to Mono/master
Comment 2 Miguel de Icaza [MSFT] 2015-05-15 18:28:17 UTC
Tests are here: mono/f1778d1797ad80109890c2cbcb76b1e2b8e08b05