XML Array Serialization Using XML Code Annotations

Question

I am struggling to serialize the following XML code...

<Activity mc:Ignorable="sap sap2010 sads" x:Class="Main"
 xmlns="http://schemas.microsoft.com/netfx/2009/xaml/activities"
 xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
 xmlns:sco="clr-namespace:System.Collections.ObjectModel;assembly=mscorlib"
 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<TextExpression.NamespacesForImplementation>
    <sco:Collection x:TypeArguments="x:String">
      <x:String>System.Activities</x:String>
      <x:String>System.Activities.Statements</x:String>
      <x:String>System.Activities.Expressions</x:String>
      <x:String>System.Activities.Validation</x:String>
      <x:String>System.Activities.XamlIntegration</x:String>
      <x:String>Microsoft.VisualBasic</x:String>
      <x:String>Microsoft.VisualBasic.Activities</x:String>
      <x:String>System</x:String>
      <x:String>System.Collections</x:String>
      <x:String>System.Collections.Generic</x:String>
      <x:String>System.Data</x:String>
      <x:String>System.Diagnostics</x:String>
      <x:String>System.Drawing</x:String>
      <x:String>System.IO</x:String>
      <x:String>System.Linq</x:String>
      <x:String>System.Net.Mail</x:String>
      <x:String>System.Xml</x:String>
      <x:String>System.Xml.Linq</x:String>
      <x:String>UiPath.Core</x:String>
      <x:String>System.Windows.Markup</x:String>
      <x:String>UiPath.Core.Activities</x:String>
    </sco:Collection>
  </TextExpression.NamespacesForImplementation>
</Activity>

I feel I have tried all combinations of [XmlArray] and [XmlArrayItem] on various properties but I can's seem to capture both the TypeArguments attribute and the list of string values. I am also unsure on which classes I need to produce to make this work. Any suggestions?

Note I have also tried using the 'Special Paste' option to generate the class structure, but after serializing and immediately deserializing, the output xml file is not of the same structure.

Do you have Visual Studio 2012+? If so, try method 2 from [this answer](https://stackoverflow.com/a/19613934/4416750). If not, try method 1 :) — Lews Therin, Jan 28 '19 at 21:58
@LewsTherin I do and I have tried this too. Seems to completely ignore this part of the XML file for some reason! I have therefore been forced to attempt it manually. — unknownpresense, Jan 28 '19 at 22:00
Did you run the XML through an XML validator? If the XML is invalid those two methods won't work properly. — Lews Therin, Jan 28 '19 at 22:05
Can you show more of your xml (say with the namespaces, and make it valid XML)? That way, we could try to repro your issue. — Flydog57, Jan 28 '19 at 22:31
@Flydog57 Sure thing. I will add it to the original post. I have also validated this to be valid xml. — unknownpresense, Jan 28 '19 at 23:07
Well, I thought I knew how to do it, but I've spent too much time at it so I'm giving up. What I did was make a `Collection` class that implemented `IList` and that, for good measure, had an indexed property (`public string this[int i]`). It also had a string property named `TypeArguments`. That allowed me to put a `XmlArray` and `XmlArrayItem` attributes on the `Collection` member of my `TextExpressionNamespacesForImplementation` class. It deserializes without error, but it doesn't populate my `Collection` instance. I hope that there's some hints in here that help you — Flydog57, Jan 29 '19 at 00:52
@Flydog57 Haha I thought the same thing to begin with too! Spent a few evenings on it but still got no where, hence my post :) Solution in chosen answer worked for me perfectly! — unknownpresense, Jan 29 '19 at 23:47

score 2 · Accepted Answer · answered Jan 29 '19 at 03:32

The following works for me.

Classes used for serializing and deserializing:

[XmlRoot(Namespace = "http://schemas.microsoft.com/netfx/2009/xaml/activities")]
public class Activity
{
    [XmlAttribute(Namespace = "http://schemas.microsoft.com/netfx/2009/xaml/activities")]
    public string Ignorable { get; set; }

    [XmlAttribute(Namespace = "http://schemas.microsoft.com/winfx/2006/xaml")]
    public string Class { get; set; }

    [XmlElement("TextExpression.NamespacesForImplementation")]
    public NamespacesForImplementation NamespacesForImplementation { get; set; }
}

public class NamespacesForImplementation
{
    [XmlElement(Namespace = "clr-namespace:System.Collections.ObjectModel;assembly=mscorlib")]
    public NamespaceCollection Collection { get; set; }
}

public class NamespaceCollection
{
    [XmlAttribute(Namespace = "http://schemas.microsoft.com/winfx/2006/xaml")]
    public string TypeArguments { get; set; }

    [XmlElement(ElementName = "String", Namespace = "http://schemas.microsoft.com/winfx/2006/xaml")]
    public List<string> Content { get; set; }
}

Test program serializing the exact XML in your question:

class Program
{
    static void Main(string[] args)
    {
        var serializer = new XmlSerializer(typeof(Activity));

        Activity activity;
        using (var stream = File.OpenText("Test.xml"))
        {
            activity = (Activity) serializer.Deserialize(stream);
        }

        XmlSerializerNamespaces ns = new XmlSerializerNamespaces();
        ns.Add(string.Empty, "http://schemas.microsoft.com/netfx/2009/xaml/activities");
        ns.Add("mc", "http://schemas.openxmlformats.org/markup-compatibility/2006");
        ns.Add("sco", "clr-namespace:System.Collections.ObjectModel;assembly=mscorlib");
        ns.Add("x", "http://schemas.microsoft.com/winfx/2006/xaml");

        using (var stringWriter = new StringWriter())
        {
            serializer.Serialize(stringWriter, activity, ns);
            Console.WriteLine(stringWriter.ToString());
        }
    }
}

The output of the program is the following:

<?xml version="1.0" encoding="utf-16"?>
<Activity xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:sco="clr-namespace:System.Collections.ObjectModel;assembly=mscorlib" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" x:Class="Main" xmlns="http://schemas.microsoft.com/netfx/2009/xaml/activities">
  <TextExpression.NamespacesForImplementation>
    <sco:Collection x:TypeArguments="x:String">
      <x:String>System.Activities</x:String>
      <x:String>System.Activities.Statements</x:String>
      <x:String>System.Activities.Expressions</x:String>
      <x:String>System.Activities.Validation</x:String>
      <x:String>System.Activities.XamlIntegration</x:String>
      <x:String>Microsoft.VisualBasic</x:String>
      <x:String>Microsoft.VisualBasic.Activities</x:String>
      <x:String>System</x:String>
      <x:String>System.Collections</x:String>
      <x:String>System.Collections.Generic</x:String>
      <x:String>System.Data</x:String>
      <x:String>System.Diagnostics</x:String>
      <x:String>System.Drawing</x:String>
      <x:String>System.IO</x:String>
      <x:String>System.Linq</x:String>
      <x:String>System.Net.Mail</x:String>
      <x:String>System.Xml</x:String>
      <x:String>System.Xml.Linq</x:String>
      <x:String>UiPath.Core</x:String>
      <x:String>System.Windows.Markup</x:String>
      <x:String>UiPath.Core.Activities</x:String>
    </sco:Collection>
  </TextExpression.NamespacesForImplementation>
</Activity>

Thank you very much, this worked for me :D This also allowed me to identify my error: I kept trying to use `[XmlArray]` or `[XmlArrayItem]` on the `List` instead of `[XmlElement]`. — unknownpresense, Jan 29 '19 at 23:51
Very slick. I wondered down the same path as @unknownpresense, and that leads nowhere. I was about to suggest hand implementing `IXmlSerializable` on the Collection class. This is **so** much better a solution. — Flydog57, Jan 30 '19 at 00:02

XML Array Serialization Using XML Code Annotations

1 Answers1