Question

I have a Repository Class with the following method…

public T Single<T>(Predicate<T> expression)
{
    using (var list = (Models.Collectable<T>)System.Xml.Serializer.Deserialize(typeof(Models.Collectable<T>), FileName))
    {
        return list.Find(expression);
    }
}

Where Collectable is defined..

[Serializable]
public class Collectable<T> : List<T>, IDisposable
{
    public Collectable() { }

    public void Dispose() { }
}

And an Item that uses it is defined..

[Serializable]
[System.Xml.Serialization.XmlRoot("Titles")]
public partial class Titles : Collectable<Title>
{
}

The problem is when I call the method, it expects “Collectable” to be the XmlRoot, but the XmlRoot is “Titles” (all of object Title).

I have several classes that are collected in .xml files like this, but it seems pointless to rewrite the basic methods for loading each up when the generic accessors do it – but how can I enforce the proper root name for each file without hard coding methods for each one? The [System.Xml.Serialization.XmlRoot] seems to be ignored.

When called like this…

var titles = Repository.List<Models.Title>(); 

I get the exception

<Titlesxmlns=''> was not expected. 

The XML is formatted such as. ..

<?xml version="1.0" encoding="utf-16"?>
<Titles xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
    <Title>
        <Id>442daf7d-193c-4da8-be0b-417cec9dc1c5</Id>
    </Title>
</Titles>

Here is the deserialization code.

  public static T Deserialize<T>(String xmlString)
    {
        System.Xml.Serialization.XmlSerializer XmlFormatSerializer
            = new System.Xml.Serialization.XmlSerializer(typeof(T));

        StreamReader XmlStringReader = new StreamReader(xmlString);

        //XmlTextReader XmlFormatReader = new XmlTextReader(XmlStringReader);

        try
        {
            return (T)XmlFormatSerializer.Deserialize(XmlStringReader);
        }
        catch (Exception e)
        {
            throw e;
        }
        finally
        {
            XmlStringReader.Close();
        }
    }

Answer 1

It makes no sense for the root of a document to be a collection. It may contain a collection, but it cannot be one.

---

Your problem appears to be simpler. You cannot create a serializer using an open generic type (Models.Collectable<T>). Try using typeof(Titles) instead.

---

I’m making some assumptions about your repository classes, but would something like this work?

public class Repository<T>
{
    protected static TextReader FileName { get; set; }

    public static TCollection List<TCollection>()
    {
        var ser = new XmlSerializer(typeof (TCollection));
        return (TCollection) ser.Deserialize(FileName);
    }

    public static TItem Single<TItem, TCollection>(Predicate<TItem> expression) 
        where TCollection : IDisposable, IEnumerable<TItem>
    {
        using (var list = List<TCollection>())
        {
            return list.Single(item => expression(item));
        }
    }
}