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Deserializing XML with empty array returns an array with a single object

When deserializing an XML containing an empty array I expect this array to be null. Instead, I get an array with a single object with all properties set to null.
Classes:
[XmlRoot(ElementName = "item")]
public class Item
{
[XmlElement(ElementName = "name")]
public string Name { get; set; }
}
[XmlRoot(ElementName = "thing")]
public class Thing
{
[XmlElement(ElementName = "items")]
public Item[] Items { get; set; }
}
XML:
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<thing>
<items/>
</thing>
Test:
[Fact]
public void DeserializeTest()
{
var xml = ""; // XML here
var serializer = new XmlSerializer(typeof(Thing));
using (TextReader reader = new StringReader(xml))
{
var thing = serializer.Deserialize(reader) as Thing;
thing.Items.Should().BeNull(); // fails
}
}
What I get:
I must be missing something?

You should use XmlArray attribute to define your array. This declaration should work:
[XmlRoot("item")]
public class Item
{
[XmlElement("name")]
public string Name { get; set; }
}
[XmlRoot(ElementName = "thing")]
public class Thing
{
[XmlArray("items")]
public Item[] Items { get; set; }
}

Here is what I believe is the problem: You are mapping the tag <Items> (with a s) to a object with an property called Items (with a s) of the type array of Item (without a s) that is mapped to the tag <Item> (without a s), and this is causing a confusion.
It does make sense that there is a Item there because you do have an <Items/> tag in your XML. And it does make sense that this Item is null because there is nothing inside the tag <Items/>
I think a XML with items in it would be something like:
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<thing>
<items>
<item name="some name"/>
</items>
</thing>
In this case your Items would be a one item list with an item object. Do understand what I mean?
Try running your code with more than one <Items> tag or without any and you will see the result.

Cannot deserialize sub-elements to list of objects

I am having problems serializing elements of an XML to a list of objects.
This is the XML:
<result>
<stats>
<numitemsfound>1451</numitemsfound>
<startfrom>0</startfrom>
</stats>
<items>
<item>
<id>1</id>
<markedfordeletion>0</markedfordeletion>
<thumbsrc>
</thumbsrc>
<thumbsrclarge>
</thumbsrclarge>
...
<datasource>65</datasource>
<data>
<amount>100</amount>
<kj>389</kj>
<kcal>92.91</kcal>
<fat_gram>0.2</fat_gram>
<fat_sat_gram>-1</fat_sat_gram>
<kh_gram>20.03</kh_gram>
</data>
<servings>
<serving>
<serving_id>386</serving_id>
<weight_gram>150</weight_gram>
</serving>
</servings>
</item>
</result>
The classes I prepared for serialization are
[XmlType("item")]
public class Item
{
[XmlAttribute("id")]
public string id { get; set; }
[XmlAttribute("markedfordeletion")]
public string markedfordeletion { get; set; }
...
[XmlAttribute("datasource")]
public string datasource { get; set; }
[XmlElement("data")]
public Data data { get; set; }
[XmlElement("servings")]
public List<Serving> servings { get; set; }
}
}
This is how I try to serialize the xml
public void ParseSearch(string xml)
{
XmlSerializer serializer = new XmlSerializer(typeof(List<Item>), new XmlRootAttribute("item"));
StringReader stringReader = new StringReader(xml);
var productList = (List<Item>)serializer.Deserialize(stringReader);
}
But I get the error ----> System.InvalidOperationException : <result xmlns=''> was not expected. Can you please help me solve this problem?

You have to use a serializer which serializes an instance of result, not of type List:
XmlSerializer serializer = new XmlSerializer(typeof(Result), new XmlRootAttribute("result")); //whatever `Result` actually is as type).
You can´t serialize and de-serialize just parts of a document, either the whole one or nothing at all.
So you need a root-type:
[XmlRoot("result")]
public class Result
{
public Stats Stats {get; set;}
[XmlArray("items")]
[XmlArrayItem("item")]
public List<Item> Items { get; set; }
}

C# Deserialization xml file

I try to deserialize xml file:
<?xml version="1.0" encoding="utf-8"?>
<XmlFile xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<OBJECTS ITEM="ItemValue" TABLE_NAME="TableExample">
</OBJECTS>
</XmlFile>
My deserialize class code looks like that:
[Serializable]
[XmlRoot("XmlFile")]
public class SerializeObject
{
[XmlAttribute("ITEM")]
public string Item { get; set; }
[XmlAttribute("TABLE_NAME")]
public string Table_Name { get; set; }
}
When I try deserialize xml file i always got no errors and Item and Table_Name equals null. Why?
Thx for replay

[XmlRoot("XmlFile")]
public class SerializableContainer
{
[XmlElement("OBJECTS")]
public SerializeObject[] Objects { get; set; }
}
public class SerializeObject
{
[XmlAttribute("ITEM")]
public string Item { get; set; }
[XmlAttribute("TABLE_NAME")]
public string Table_Name { get; set; }
}
And then you deserialize with:
var serializer = new XmlSerializer(typeof(SerializableContainer));
using (var file = File.OpenText("sample.xml"))
{
var data = (SerializableContainer)serializer.Deserialize(file);
// ...
}

leaving here a more complete example in case anyone needs: http://davidsonsousa.net/en/post/serializedeserialize-objects-to-xml-with-c
Cheers!

Deserialize XML to Object Array

I'm trying to deserialize an XML file to an object array, but I'm receiving empty objects.
My question looks similar to this: How to Deserialize xml to an array of objects? but I can't seem to create a class which inherits IXmlSerializable. That said, I don't think that approach is necessary.
Am I doing something wrong?
File Object
[XmlType("file")]
public class File
{
[XmlElement("id")]
public string Id { get; set; }
[XmlElement("company_name")]
public string Company_Name { get; set; }
[XmlElement("docs")]
public HashSet<doc> Docs { get; set; }
}
Doc Object
[XmlType("doc")]
public class Doc
{
[XmlElement("valA")]
public string ValA { get; set; }
[XmlElement("valB")]
public string ValB { get; set; }
}
XML
<?xml version="1.0" encoding="UTF-8"?>
<files>
<file>
<id>12345</id>
<company_name>Apple</company_name>
<docs>
<doc>
<valA>Info</valA>
<valB>More Info</valB>
</doc>
</docs>
</file>
<file>
<id>12345</id>
<company_name>Microsoft</company_name>
<docs>
<doc>
<valA>Even More Info</valA>
<valB>Lots of it</valB>
</doc>
</docs>
</file>
</files>
Deserialization code
XmlSerializer mySerializer = new XmlSerializer(typeof(File[]), new XmlRootAttribute("files"));
using (FileStream myFileStream = new FileStream("Files.xml", FileMode.Open))
{
File[] r;
r = (File[])mySerializer.Deserialize(myFileStream);
}

You have decorated your properties with XMLAttribute but they are elements in your XML. So, change all XMLAttribute to XmlElement.
[XmlType("file")]
public class File
{
[XmlElement("id")]
public string Id { get; set; }
[XmlElement("company_name")]
public string Company_Id { get; set; }
[XmlArray("docs")]
public HashSet<Doc> Docs { get; set; }
}
[XmlType("doc")]
public class Doc
{
[XmlElement("valA")]
public string ValA { get; set; }
[XmlElement("valB")]
public string ValB { get; set; }
}
Also you XML is not well formed. I guess this is typo though -
<company_name>Apple</company_id>
<company_name>Microsoft</company_id>
Ending tag should be company_name -
<company_name>Apple</company_name>
<company_name>Microsoft</company_name>

I would use xml parser..
XDocument doc=XDocument.Load(url);
File[] r=doc.Elements("file")
.Select(f=>
new File
{
Id=f.Element("id").Value,
Company_Id=f.Element("company_name").Value,
Docs=new HashSet<Docs>(
f.Elements("docs")
.Elements("doc")
.Select(d=>
new Doc
{
ValA=d.Element("valA").Value,
ValB=d.Element("valB").Value
}))
}).ToArray();

Get null by deserialize in C# from XML if string between tags

i need some help, i get allways null if i will deserialize a string between two xml tags.
The following example xml file:
<?xml version="1.0" encoding="utf-8" ?>
<item name='First Item' size='1'>
<Bits value='0'>
1st String
</Bits>
<Bits value='1'>
2nd String
</Bits>
</item>
And i write the following classes:
[Serializable()]
public class Bits
{
[XmlElement(ElementName = "Bits")]
public String entryString { get; set; }
[XmlAttribute("value")]
public int entryValue { get; set; }
}
[Serializable()]
[XmlRoot("item")]
public class itemsReader
{
public itemsReader()
{
_bitList = new List<Bits>();
}
[XmlElement("Bits")]
public List<Bits> _bitList { get; set; }
[XmlAttribute("name")]
public String entryName { get; set; }
[XmlAttribute("size")]
public int entrySize { get; set; }
}
Only the entryString is always null!
To readout the XML file i use the following:
itemsReader ireader = null;
String path = #"PathtoString";
XmlSerializer serializer = new XmlSerializer(typeof(itemsReader));
var reader = File.OpenText(path);
ireader = (itemsReader)serializer.Deserialize(reader);
Thanks for help!

You have decorated entryString with XmlElement attribute which will search for an element Bits inside Bits itself.
But you want inner text of Bits element. For that we have another attribute called XmlText.
So change this
[XmlElement(ElementName = "Bits")]
public String entryString { get; set; }
to
[XmlText]
public String entryString { get; set; }

i ran your code on your input and got the output, but the i saw, in the Bits class, that the property entryString has an attribute
[XmlElement(ElementName = "Bits")]
but in your xml file there is no <Bits> tags around 1st String. so i added them and got:
<?xml version="1.0"?>
<item name="First Item" size="2">
<Bits value="1">
<Bits>firstOne</Bits>
</Bits>
<Bits value="2">
<Bits>secOne</Bits>
</Bits>
</item>
and then your code worked
so you can change the xml file or get rid of the attribute. your call