IEnumerable(of String) ignored by XmlSerializer

» .net » IEnumerable(of String) ignored by XmlSerializer

By : LHuntington

Date : November 26 2020, 06:28 AM

To fix this issue For one of my object, I need to do some backward/forward compatibility tricks so that everyone is happy while different versions coexist and share the same config file. , You have a few issues here:

code :

[System.InvalidOperationException: To be XML serializable, types which inherit from IEnumerable must have an implementation of Add(System.Object) at all levels of their inheritance hierarchy. EnumerableBridge`2[[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[CategoryInfo, 58be8a1c-a824-4133-9ef8-b2552cccedab, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null]] does not implement Add(System.Object).]

' <Serializable> Removed since _converterFrom and _add are not really serializable
Public Class EnumerableBridge(Of TSource, TTarget)
    Implements IEnumerable(Of TSource)

    Private _refCollection As IList(Of TTarget)
    Private _add As Action(Of IList(Of TTarget), TSource)
    Private _converterFrom As Func(Of TTarget, TSource)

    Sub New()
        Throw New NotImplementedException()
    End Sub

    Public Sub New(refCollection As IList(Of TTarget), add As Action(Of IList(Of TTarget), TSource), converterFrom As Func(Of TTarget, TSource))
        _refCollection = refCollection
        _add = add
        _converterFrom = converterFrom
    End Sub

    Public Sub Add(item As TSource) 'Implements ICollection(Of TSource).Add
        _add(_refCollection, item)
    End Sub

    Public Function IEnumerable_GetEnumerator() As IEnumerator Implements IEnumerable.GetEnumerator
        Return GetEnumerator()
    End Function

    Public Function GetEnumerator() As IEnumerator(Of TSource) Implements IEnumerable(Of TSource).GetEnumerator
        Return _refCollection.Select(_converterFrom).GetEnumerator()
    End Function
End Class

Public Class OptionsSerializable
    Public Sub New()
    End Sub

    <XmlAnyElement>
    Public Property Unsupported As List(Of XmlElement)

    <System.Xml.Serialization.XmlElement(ElementName:="ListeCategoriesExt")>
    Public ReadOnly Property Categories As List(Of CategoryInfo) = New List(Of CategoryInfo)

    Shared Sub AddCategory(Categories as IList(Of CategoryInfo), Name as String)
        If Not Categories.Any(Function(c) c.SearchTerm = Name) Then
            Categories.Add(New CategoryInfo(Name))
        End If
    End Sub

    Public ReadOnly Property ListeCategories As EnumerableBridge(Of String, CategoryInfo) = New EnumerableBridge(Of String, CategoryInfo)(_categories, AddressOf AddCategory, Function(c) c.SearchTerm)

    ' Remainder unchanged

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How can I use IEnumerable interface and at the same time, have XMLSerializer not use GetEnumerator()?

By : Yuks

Date : March 29 2020, 07:55 AM

seems to work fine I managed to fix this problem without having to change my design. None of my code was relying on the IEnumerable interface, just the implementation of IEnumerable GetEnumerator() (apparently foreach doesn't check to see if IEnumerable is implemented). Just commenting out the interface in the class declaration did the trick.

XmlSerializer and IEnumerable: Serialization possible w/o parameterless constructor: Bug?

By : user2641024

Date : March 29 2020, 07:55 AM

To fix this issue The reason for the behavior is that this is the way it has always worked.
From XmlSerializer class:

XmlSerializer - IEnumerable or IList as LIst

By : merbng

Date : March 29 2020, 07:55 AM

it fixes the issue Since you can't change the class, create a new class, inheriting from the class you want to serialize and from IXmlSerializable. In addition, you can override the base Colors array with the new keyword.
Try this one:

code :

public class Something
{
    public int Id { get; set; }

    public string Text { get; set; }

    public IEnumerable<string> Colors { get; set; }
}

public class MySerializableSomething : Something, IXmlSerializable
{
    public new List<string> Colors { get; set; }

    public MySerializableSomething()
    {
        Colors = new List<string>();
    }

    public XmlSchema GetSchema()
    {
        return null;
    }

    public void ReadXml(XmlReader reader)
    {
        while (reader.Read())
        {
            switch (reader.LocalName)
            {
                case "Id": Id = reader.ReadElementContentAsInt(); break;
                case "Text": Text = reader.ReadElementContentAsString(); break;
                case "Color": Colors.Add(reader.ReadElementContentAsString()); break;
            }
        }
    }

    public void WriteXml(XmlWriter writer)
    {
        writer.WriteElementString("Id", Id.ToString());
        writer.WriteElementString("Text", Text);

        writer.WriteStartElement("Colors");

        foreach (var color in Colors)
        {
            writer.WriteElementString("Color", color);
        }

        writer.WriteEndElement();
    }
}

XmlSerializer not deserializing XML to IEnumerable

By : user3541820

Date : March 29 2020, 07:55 AM

To fix this issue When your XML-serialized type has a property of type List, XmlSerializer will get the value of the property, then call .Add(...) to add the deserialized elements (i.e. it does not set the property).
Since the getter for the GlossarySurrogate property returns a new list every time you get it, the changes the XML serializer makes to the result are lost.