Bug 11801 - DataContractSerializer: data serialized on MonoTouch is deserialized wrong on Win (IList<IIterface>)
Summary: DataContractSerializer: data serialized on MonoTouch is deserialized wrong on...
Alias: None
Product: iOS
Classification: Xamarin
Component: BCL Class Libraries ()
Version: 6.0.x
Hardware: PC Mac OS
: --- normal
Target Milestone: Untriaged
Assignee: Bugzilla
Depends on:
Reported: 2013-04-16 05:51 UTC by Artur
Modified: 2017-01-25 17:44 UTC (History)
4 users (show)

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

Small test console app. (26.34 KB, application/x-zip-compressed)
2017-01-25 17:16 UTC, Manuel de la Peña [MSFT]

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Description Artur 2013-04-16 05:51:14 UTC
If I serialize data under MonoTouch and then try to deserialize on Win with .net framework the results differ.
The problem is that serialization of List<IItem> differs significantly.

The following are data structures:
namespace Tst

    public interface IItem
    [DataContract(Namespace = "Tst")]
    public class Item : IItem
        public int A { get; set; }
    [DataContract(Namespace = "Tst"), KnownType(typeof(Item))]
    public class Data
        public IList<IItem> Items1 { get; set; }
    public class Tests2
        public void Test()
            var value = new Data()
                Items1 = new List<IItem>() { new Item() { A = 1 } },
            var sb = new StringBuilder();
            var xmlWriter = new XmlTextWriter(new StringWriter(sb));
            DataContractSerializer dataContractSerializer = new DataContractSerializer(typeof(Data));
            dataContractSerializer.WriteObject(xmlWriter, value);

            var serializedStringFromMonoTouch =
                "<Data xmlns:i=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns=\"Tst\"><Items1 xmlns:d2p1=\"http://schemas.datacontract.org/2004/07/Tst\"><d2p1:IItem i:type=\"Item\"><A>1</A></d2p1:IItem></Items1></Data>";
            var obj = (Data)dataContractSerializer.ReadObject(new XmlTextReader(new StringReader(dt)));
            Assert.AreEqual(obj.Items1.Count, 1);

Here's the string when serialized on Windows with .Net framework:
<Data xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="Tst"><Items1 xmlns:d2p1="http://schemas.microsoft.com/2003/10/Serialization/Arrays"><d2p1:anyType i:type="Item"><A>1</A></d2p1:anyType></Items1></Data>
String when serialized under MonoTouch is given within a test.

Assertion in a test fails.
Comment 1 Manuel de la Peña [MSFT] 2017-01-11 11:10:55 UTC

Running the example code on a Mac OS with XS and Mono 4.6.2 (mono-4.6.0-branch/ac9e222) (64-bit) I get the following serialisation:

<Data xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="Tst"><Items1 xmlns:d2p1="http://schemas.microsoft.com/2003/10/Serialization/Arrays"><d2p1:anyType i:type="Item"><A>1</A></d2p1:anyType></Items1></Data>

While on a Windows Machine with VS Studio I get the following one:

<Data xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="Tst"><Items1><Item><A>1</A></Item></Items1></Data>

Looks like even when the Namespace value is passed to the DataContract attributes the generated code does not remove them.
Comment 2 Manuel de la Peña [MSFT] 2017-01-25 17:16:55 UTC
Created attachment 19479 [details]
Small test console app.
Comment 3 Manuel de la Peña [MSFT] 2017-01-25 17:44:40 UTC
The above test was done using mono 4.6, with mono 4.8 we share the serialisation with .Net core and the following is returned from the attached example app:

<Data xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="Tst"><Items1><Item><A>1</A></Item></Items1></Data>

Therefore the result is the same and will close the bug as invalid.