Bug 16028 - WriteXml / ReadXml methods ignored for IXmlSerializable implementated classes
Summary: WriteXml / ReadXml methods ignored for IXmlSerializable implementated classes
Alias: None
Product: Class Libraries
Classification: Mono
Component: System.XML ()
Version: 3.2.x
Hardware: Macintosh Mac OS
: --- normal
Target Milestone: Untriaged
Assignee: Bugzilla
Depends on:
Reported: 2013-11-07 23:56 UTC by Aaron Henselin
Modified: 2015-05-15 04:37 UTC (History)
3 users (show)

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

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Description Aaron Henselin 2013-11-07 23:56:11 UTC
Classes implementing IXmlSerizalable do not have their ReadXml / WriteXml methods read. For instance, a dictionary with custom serialization might have the method:

        public void WriteXml(XmlWriter writer)
            foreach (var key in Keys)

On .NET this produces expected results of 

On Mono, this method is ignored, and produces key value pairs using default xml serialization:
<SerializableDictionaryOfStringString xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.microsoft.com/2003/10/Serialization/Arrays"><KeyValueOfstringstring><Key>OS</Key><Value>Windows</Value></KeyValueOfstringstring><KeyValueOfstringstring><Key>Version</Key><Value>95</Value></KeyValueOfstringstring><KeyValueOfstringstring></KeyValueOfstringstring></SerializableDictionaryOfStringString>

For reference, serialization is being handled through a datacontractserializer:
        public static string Serialize(Type type, object val)
            if (type == null) { throw new ArgumentNullException("type"); }
            if (val == null) { throw new ArgumentNullException("val"); }

            var builder = new StringBuilder();
            var serializer = new DataContractSerializer(type);
            var xmlWriter = XmlWriter.Create(builder);
            serializer.WriteObject(xmlWriter, val);

            return builder.ToString().Replace("<?xml version=\"1.0\" encoding=\"utf-16\"?>", string.Empty)

Comment 1 henrik 2014-04-23 17:48:31 UTC
+1 to fix this one; important for dealing with non-C# languages, e.g.:

/// string argument is SummaryText
type Duration =
  | Regular of string
  | Temporary of TemporaryDuration * string
  interface IXmlSerializable with
    member x.ReadXml(r : XmlReader) =
      failwith "not implemented"
    member x.WriteXml(w : XmlWriter) =
      let summary =
        match x with
        | Regular summary_text ->
          w.WriteStartElement "Regular"
        | Temporary(temp_dur, summary_text) ->
          w.WriteStartElement "Temporary"
          w.WriteElementString("TermLength", (int temp_dur).ToString())
      w.WriteElementString("SummaryText", summary)
    member x.GetSchema() =
Comment 2 henrik 2014-04-23 17:52:27 UTC
Here's the line of code that is run, when it should not be run:

Comment 3 Marek Safar 2015-05-15 04:37:27 UTC
Fixed in master