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Deserializing an XML into a object: XML element with xsi:nil="true" should have null value (and not empty value) for respective property in object

When de-serializing the below XML into Parent class, ElementTwo and ElementThree are empty strings, which is expected. But ElementOne should have been null but instead this is also empty string.
What does i:nil="true" mean?
XML
<?xml version = \"1.0\" ?>
<Parent
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<ElementOne xsi:nil="true"/>
<ElementTwo></ElementTwo>
<ElementThree />
<ElementFour>Value</ElementFour>
</Parent>
C# Class
public class Parent
{
public string ElementOne { get; set; }
public string ElementTwo { get; set; }
public string ElementThree { get; set; }
public string ElementFour { get; set; }
}
When de-serializing the XML into an object, the XML element with xsi:nil="true" is not being converted as null. Instead, it is assigned as empty string. But I've a requirement where it should be converted as null only. Please help me to figure out a solution or point put where I went wrong
I've given the sample used in below fiddle link:
https://dotnetfiddle.net/VfNJYv

Put
[XmlElement(IsNullable=true)]
above the
Public string ElementOne get/set property
.NET fiddle

how should I prevent the XML-serialized model from automatically generating tags? [duplicate]

Can I somehow disable rendering of root element of collection?
This class with serialization attributes:
[XmlRoot(ElementName="SHOPITEM", Namespace="")]
public class ShopItem
{
[XmlElement("PRODUCTNAME")]
public string ProductName { get; set; }
[XmlArrayItem("VARIANT")]
public List<ShopItem> Variants { get; set; }
}
generates this XML:
<SHOPITEM xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<PRODUCTNAME>test</PRODUCTNAME>
<Variants>
<VARIANT>
<PRODUCTNAME>hi 1</PRODUCTNAME>
</VARIANT>
<VARIANT>
<PRODUCTNAME>hi 2</PRODUCTNAME>
</VARIANT>
</Variants>
</SHOPITEM>
I don't want <Variants> element here. What must I do?
Also I don't need xsi and xsd namespaces in root element...

To disable rendering of root element of collection, you must replace the attribute [XmlArrayItem] with [XmlElement] in your code.
For removing the xsi and xsd namespaces, create an XmlSerializerNamespaces instance with an empty namespace and pass it when you need to serialize your object.
Take a look on this example:
[XmlRoot("SHOPITEM")]
public class ShopItem
{
[XmlElement("PRODUCTNAME")]
public string ProductName { get; set; }
[XmlElement("VARIANT")] // was [XmlArrayItem]
public List<ShopItem> Variants { get; set; }
}
// ...
ShopItem item = new ShopItem()
{
ProductName = "test",
Variants = new List<ShopItem>()
{
new ShopItem{ ProductName = "hi 1" },
new ShopItem{ ProductName = "hi 2" }
}
};
// This will remove the xsi/xsd namespaces from serialization
XmlSerializerNamespaces ns = new XmlSerializerNamespaces();
ns.Add("", "");
XmlSerializer ser = new XmlSerializer(typeof(ShopItem));
ser.Serialize(Console.Out, item, ns); // Inform the XmlSerializerNamespaces here
I got this output:
<?xml version="1.0" encoding="ibm850"?>
<SHOPITEM>
<PRODUCTNAME>test</PRODUCTNAME>
<VARIANT>
<PRODUCTNAME>hi 1</PRODUCTNAME>
</VARIANT>
<VARIANT>
<PRODUCTNAME>hi 2</PRODUCTNAME>
</VARIANT>
</SHOPITEM>

Replace [XmlArrayItem("VARIANT")] with [XmlElement("VARIANT")].

I don't believe it is possible to remove this element using the default xml serialization (with attributes). If you could do this, then serializing your ShopItem class would result in badly formed xml (no root element) for the object, which is not allowed.
What you can do however, is manually implement IXmlSerializable. This will give you the sort of fine-grained control you a re after.
[Edit] - sorry - misread that you were trying to remove Variants, not SHOPITEM. To remove the List "outer" element, just mark it up with an [XmlElement] attribute rather than an [XmlArrayItem] attribute. This will cause the list entries to just use the specified element name, without wrapping the list in an outer element.
For removing the namespaces, this is controlled by the seriliazer itself, not the markup on the class.
I've just noticed that while I've updated this answer, Rubens Farias has provided an reply that shows you how to eliminate the namespace.

C# XML-Serialization -> Get rid of a hierarchy level [duplicate]

Can I somehow disable rendering of root element of collection?
This class with serialization attributes:
[XmlRoot(ElementName="SHOPITEM", Namespace="")]
public class ShopItem
{
[XmlElement("PRODUCTNAME")]
public string ProductName { get; set; }
[XmlArrayItem("VARIANT")]
public List<ShopItem> Variants { get; set; }
}
generates this XML:
<SHOPITEM xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<PRODUCTNAME>test</PRODUCTNAME>
<Variants>
<VARIANT>
<PRODUCTNAME>hi 1</PRODUCTNAME>
</VARIANT>
<VARIANT>
<PRODUCTNAME>hi 2</PRODUCTNAME>
</VARIANT>
</Variants>
</SHOPITEM>
I don't want <Variants> element here. What must I do?
Also I don't need xsi and xsd namespaces in root element...

To disable rendering of root element of collection, you must replace the attribute [XmlArrayItem] with [XmlElement] in your code.
For removing the xsi and xsd namespaces, create an XmlSerializerNamespaces instance with an empty namespace and pass it when you need to serialize your object.
Take a look on this example:
[XmlRoot("SHOPITEM")]
public class ShopItem
{
[XmlElement("PRODUCTNAME")]
public string ProductName { get; set; }
[XmlElement("VARIANT")] // was [XmlArrayItem]
public List<ShopItem> Variants { get; set; }
}
// ...
ShopItem item = new ShopItem()
{
ProductName = "test",
Variants = new List<ShopItem>()
{
new ShopItem{ ProductName = "hi 1" },
new ShopItem{ ProductName = "hi 2" }
}
};
// This will remove the xsi/xsd namespaces from serialization
XmlSerializerNamespaces ns = new XmlSerializerNamespaces();
ns.Add("", "");
XmlSerializer ser = new XmlSerializer(typeof(ShopItem));
ser.Serialize(Console.Out, item, ns); // Inform the XmlSerializerNamespaces here
I got this output:
<?xml version="1.0" encoding="ibm850"?>
<SHOPITEM>
<PRODUCTNAME>test</PRODUCTNAME>
<VARIANT>
<PRODUCTNAME>hi 1</PRODUCTNAME>
</VARIANT>
<VARIANT>
<PRODUCTNAME>hi 2</PRODUCTNAME>
</VARIANT>
</SHOPITEM>

Replace [XmlArrayItem("VARIANT")] with [XmlElement("VARIANT")].

I don't believe it is possible to remove this element using the default xml serialization (with attributes). If you could do this, then serializing your ShopItem class would result in badly formed xml (no root element) for the object, which is not allowed.
What you can do however, is manually implement IXmlSerializable. This will give you the sort of fine-grained control you a re after.
[Edit] - sorry - misread that you were trying to remove Variants, not SHOPITEM. To remove the List "outer" element, just mark it up with an [XmlElement] attribute rather than an [XmlArrayItem] attribute. This will cause the list entries to just use the specified element name, without wrapping the list in an outer element.
For removing the namespaces, this is controlled by the seriliazer itself, not the markup on the class.
I've just noticed that while I've updated this answer, Rubens Farias has provided an reply that shows you how to eliminate the namespace.

Serializing objects to xml in C#

I have a simple class Student under namespace School.
namespace XmlTestApp
{
public class Student
{
private string studentId;
public string FirstName;
public string MI;
public string LastName;
public Student()
{
//Just provided for making Serialization work as obj.GetType() needs parameterless constructor.
}
public Student(String studentId)
{
this.studentId = studentId;
}
}
}
Now when i serialize this, i get this as serialized xml:
<?xml version="1.0" encoding="utf-8"?>
<Student xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<FirstName>Cad</FirstName>
<MI>Dsart</MI>
<LastName>dss</LastName>
</Student>
But what i want is this, basically i need the namespace prefixed to class name in xml, is this possible?
<?xml version="1.0" encoding="utf-8"?>
<XmlTestApp:Student xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<FirstName>Cad</FirstName>
<MI>Dsart</MI>
<LastName>dss</LastName>
</Student>
Here's my serialization code:
Student s = new Student("2");
s.FirstName = "Cad";
s.LastName = "dss";
s.MI = "Dsart";
System.Xml.Serialization.XmlSerializer x = new System.Xml.Serialization.XmlSerializer(s.GetType());
TextWriter txtW=new StreamWriter(Server.MapPath("~/XMLFile1.xml"));
x.Serialize(txtW,s);

EDIT: Short answer is still yes. The proper attribute is actually the XmlType attribute. In addition, you will need to specify a namespace, and then in the serialization code you will need to specify aliases for the namespaces that will be used to qualitfy elements.
namespace XmlTestApp
{
[XmlRoot(Namespace="xmltestapp", TypeName="Student")]
public class Student
{
private string studentId;
public string FirstName;
public string MI;
public string LastName;
public Student()
{
//Just provided for making Serialization work as obj.GetType() needs parameterless constructor.
}
public Student(String studentId)
{
this.studentId = studentId;
}
}
}
...
Student s = new Student("2");
s.FirstName = "Cad";
s.LastName = "dss";
s.MI = "Dsart";
System.Xml.Serialization.XmlSerializer x = new System.Xml.Serialization.XmlSerializer(s.GetType());
System.Xml.Serialization.XmlSerializationNamespaces ns = new System.Xml.Serialization.XmlSerializationNamespaces();
ns.Add("XmlTestApp", "xmltestapp");
TextWriter txtW=new StreamWriter(Server.MapPath("~/XMLFile1.xml"));
x.Serialize(txtW,s, ns); //add the namespace provider to the Serialize method
You may have to play around with the setting up of the namespace to ensure it still uses the XSD/XSI from W3.org, but this should get you on the right track.

Another way how to achieve it, is to write your xml - than use tool in visual studio - xml to xsd. If you have xsd, you can generate serializeable classes with xsdToCode

An elegant solution would be to use XmlSerializerNamespaces to declare your namespace and then pass that into the XmlSerializer
See XML Serialization and namespace prefixes

Problem with C# XmlSerialization

I have xml file:
<?xml version="1.0" encoding="utf-8"?>
<LabelTypesCollection xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance="xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<LabelTypes>
<LabelType>
<Name>LabelTypeProduct</Name>
</LabelType>
<LabelType>
<Name>LabelTypeClient</Name>
</LabelType>
</LabelTypes>
</LabelTypesCollection>
And 2 c# classes:
[Serializable]
[XmlRoot("LabelTypesCollection")]
public class LabelTypesCollection
{
private static string _labelTypesCollectionPath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), Path.Combine(Program.ProgramName, "LabelTypesCollection.xml"));
[XmlArray("LabelTypes", ElementName="LabelType")]
public List<LabelType> LabelTypes { get; set; }
public static LabelTypesCollection LoadAllLabelTypes()
{
FileInfo fi = new FileInfo(_labelTypesCollectionPath);
if (!fi.Exists)
{
Logger.WriteLog("Could not find size_types_collection.xml file.", new Exception("Could not find size_types_collection.xml file."));
return new LabelTypesCollection();
}
try
{
using (FileStream fs = fi.OpenRead())
{
XmlSerializer serializer = new XmlSerializer(typeof(LabelTypesCollection));
LabelTypesCollection labelTypesCollection = (LabelTypesCollection)serializer.Deserialize(fs);
return labelTypesCollection;
}
}
catch (Exception ex)
{
Logger.WriteLog("Error during loading LabelTypesCollection", ex);
return null;
}
}
}
[Serializable]
public class LabelType
{
[XmlElement("Name")]
public string Name { get; set; }
[XmlIgnore]
public string TranslatedName
{
get
{
string translated = Common.Resources.GetValue(Name);
return (translated == null) ? Name : translated;
}
}
}
And when I call:
LabelTypesCollection.LoadAllLabelTypes();
I get LabelTypeCollection object with empty LabelTypes list. There is no error or anything. Could anyone point me to the problem?

Change this
[XmlArray("LabelTypes", ElementName="LabelType")]
to this
[XmlArray]
The ElementName of an XmlArrayAttribute specifies the element name of the container, and is actually what you specify in the first parameter to the ctor! So the ctor you have says "this class serializes as a container named LabelTypes; no wait actually I want the container to be named LabelType". The named parameter is overwriting what the first unnamed parameter says.
And in fact, since you want the container element to be named LabelTypes, which is what the member is actually called, you don't need to specify it at all.
You may have been thinking of XmlArrayItemAttribute, which controls what the individual members of a serialized collection are named - but you don't need that here either.
My usual approach for working out xml serializer stuff is to build objects manually then look at the xml they serialize to. In this case, using the code you currently have produces xml like this:
<?xml version="1.0" encoding="utf-16"?>
<LabelTypesCollection xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<LabelType>
<LabelType>
<Name>one</Name>
</LabelType>
<LabelType>
<Name>two</Name>
</LabelType>
</LabelType>
</LabelTypesCollection>
which is what tipped me off to the incorrect LabelType specifier.
Note that you also don't need the XmlRoot on LabelTypesCollection, or the XmlElement on Name, since you are just specifying what the xml serializer will come up with anyway.

Here's a suggestion.
Write a small test program that creates an instance of LabelTypesCollection, and adds some LabelType objects into it.
Then use an XmlSerializer to write the object to a file, and look at the Xml you get, to ensure that your input Xml is in the correct schema.
Maybe there's something wrong with one of your Xml elements.

I really think you get an empty list because your code can't find the xml file. Also try instantiating your list. If you have the xml path correctly.
public List<LabelType> LabelTypes = new List<LabelType>();