How to serialize an object containing an XML property - c#

Note this is .NET 4.8
I have created this sample code to illustrate the problem
[XmlRoot(ElementName = "RESULT", Namespace = "", IsNullable = false)]
public class Result
{
public string Message { get; set; }
public XElement Stuff { get; set; }
public override string ToString()
{
var ser = new XmlSerializer(GetType());
using (var stream = new StringWriter())
{
ser.Serialize(stream, this);
return stream.ToString();
}
}
}
I will have some XML already that looks like this
<FOO>
<BAR>Hello World</BAR>
<BAR2>Hello World</BAR2>
<BAR3>Hello World</BAR3>
</FOO>
This is assigned to the XElement Stuff property and when an instance of Result is then serialized, you get this XML:
<?xml version="1.0" encoding="utf-16"?>
<RESULT xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<Message>Hello World</Message>
<Stuff>
<FOO>
<BAR>Hello World</BAR>
<BAR2>Hello World</BAR2>
<BAR3>Hello World</BAR3>
</FOO>
</Stuff>
</RESULT>
Question: Is there any way to get this result instead?
<?xml version="1.0" encoding="utf-16"?>
<RESULT xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<Message>Hello World</Message>
<FOO>
<BAR>Hello World</BAR>
<BAR2>Hello World</BAR2>
<BAR3>Hello World</BAR3>
</FOO>
</RESULT>
Note: FOO could be Stuff - I don't care (because I know how to change that name) I just don't want two levels of nested XML for that property in the serialised XML
You can play with the sample code here


If you're happy for the root name to be hard-coded, then you can write a wrapper type for the elements and implement IXmlSerializable within.
This is likely preferable to implementing in Result, as I imagine the real type would have more than 2 properties.
A quick and dirty example - I'll leave implementing ReadXml to you (if you need it):
public class ElementsWrapper : IXmlSerializable
{
public XElement[] Elements { get; set; }
public XmlSchema GetSchema()
{
return null;
}
public void ReadXml(XmlReader reader)
{
}
public void WriteXml(XmlWriter writer)
{
foreach (var element in Elements)
{
element.WriteTo(writer);
}
}
}
And change your property in Result to:
public ElementsWrapper FOO { get; set; }
When used, the serialiser for Result will write <FOO>, then delegate to the custom serialisation, and then write </FOO>.
You can see an updated fiddle here.

Related

Xml Serialization: Can't define same namespace in parent and child element

i need to create a xml structure similar to this:
<?xml version="1.0" encoding="utf-8"?>
<ns0:RootElement xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:ns0="http://fuu.gub">
<ns0:ChildElement xmlns:ns0="http://fuu.gub">
<ns0:Data>Some-data</ns0:Data>
</ns0:ChildElement>
</ns0:RootElement>
The namespace ns0 must be defined in the RootElement and in the ChildElement.
I'm using Xml.Serialization to serialize my objects and i cant get this done.
The serializer is ignoring the namespace on the child element because it's already defined in the parent. This means i end up with the following result:
<?xml version="1.0" encoding="utf-8"?>
<ns0:RootElement xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:ns0="http://fuu.gub">
<ns0:ChildElement>
<ns0:Data>Some-data</ns0:Data>
</ns0:ChildElement>
</ns0:RootElement>
Here is my code
[XmlRoot("RootElement", Namespace = "http://fuu.gub")]
public class RootElement
{
[XmlNamespaceDeclarations]
public XmlSerializerNamespaces XmlNamespaces { get; set; }
[XmlElement("ChildElement")]
public ChildElement Child { get; set; }
public RootElement() {
XmlNamespaces = new XmlSerializerNamespaces();
XmlNamespaces.Add("ns0", "http://fuu.gub");
Child = new ChildElement();
}
public void ToXml(string path)
{
XmlSerializer x = new System.Xml.Serialization.XmlSerializer(this.GetType());
TextWriter txtW = new StreamWriter(path);
x.Serialize(txtW, this);
}
}
[XmlRoot(Namespace = "http://fuu.gub")]
public class ChildElement
{
[XmlNamespaceDeclarations]
public XmlSerializerNamespaces XmlNamespaces { get; set; }
[XmlElement]
public string Data{ get; set; }
public ChildElement()
{
XmlNamespaces = new XmlSerializerNamespaces();
XmlNamespaces.Add("ns0", "http://fuu.gub");
Data = "Some-data";
}
}

Here http://www.w3schools.com/xml/xml_namespaces.asp I found this:
When a namespace is defined for an element, all child elements with
the same prefix are associated with the same namespace.
Namespaces can be declared in the elements where they are used or in
the XML root element
Note: The namespace URI is not used by the parser to look up
information.
When you define a namespace, you can´t use the same prefix to define another/the same namespace again.
I believe you can use the same namespace with a different prefix though.

XML Deserialization Array

I have a class. I want to deserialize XML file into this class.
public partial class Form1 : Form
{
public string xmlFile;
public Form1()
{
InitializeComponent();
xmlFile = "Sample.xml";
}
[Serializable]
public class Application
{
public string AppName;
public string UpdateDetail;
};
[Serializable]
public class Applications
{
[XmlElement]
public Application[] Application;
};
[Serializable]
public class Pmsp_Update
{
public string OldVersion;
public string NewVersion;
public Applications Applications;
};
private void btnRead_Click(object sender, EventArgs e)
{
XmlReader reader = XmlReader.Create(xmlFile);
XmlSerializer ser = new XmlSerializer(typeof(Pmsp_Update));
Pmsp_Update pu;
using (reader = XmlReader.Create(xmlFile))
{
pu = (Pmsp_Update)ser.Deserialize(reader);
}
}
}
And here is the XML:
<Pmsp_Update>
<OldVersion>v4.0.0</OldVersion>
<NewVersion>v4.0.1</NewVersion>
<Applications>
<Application>
<AppName>SampleApp</AppName>
<UpdateDetail>sample</UpdateDetail>
</Application>
</Applications>
</Pmsp_Update>
I want to ask about attributes. I only used [Serializable] attribute and I can get the class. I don't use any [XmlElement] attribute and this didn't cause any error except one.
If I use like this I can populate the array but:
[Serializable]
public class Applications
{
[XmlElement]
public Application[] Application;
};
If I use like this I can't populate the array:
[Serializable]
public class Applications
{
public Application[] Application;
};
So, my question is this: I am not using [XmlElement] for fields and everything works well but I can't populate the array. Why couldn't I populate the array when I don't use [XmlElement] although I can populate the fields?

The easiest way to check what's going on is to create object of your class and serialize it to XML. This is what I get:
Without [XmlElement]
<?xml version="1.0" encoding="utf-16"?>
<Pmsp_Update xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<OldVersion>v4.0.0</OldVersion>
<NewVersion>v.4.0.1</NewVersion>
<Applications>
<Application>
<Application>
<AppName>Test</AppName>
<UpdateDetail>test</UpdateDetail>
</Application>
</Application>
</Applications>
</Pmsp_Update>
With [XmlElement]
<?xml version="1.0" encoding="utf-16"?>
<Pmsp_Update xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<OldVersion>v4.0.0</OldVersion>
<NewVersion>v.4.0.1</NewVersion>
<Applications>
<Application>
<AppName>Test</AppName>
<UpdateDetail>test</UpdateDetail>
</Application>
</Applications>
</Pmsp_Update>
As you can see, only the second one matches your input XML, and that's why you cannot deserialize yout XML without [XmlElement] attribute - because your XML document does not match your class structure.
Empty XmlElement on top of array property prevent serializer from expecting additional element to handle array elements. That behavior is described on MSDN: XmlElementAttribute Class
If you apply the XmlElementAttribute to a field or property that
returns an array, the items in the array are encoded as a sequence of
XML elements.
In contrast if an XmlElementAttribute is not applied to
such a field or property, the items in the array are encoded as a
sequence of elements, nested under an element named after the field or
property. (Use the XmlArrayAttribute and XmlArrayItemAttribute
attributes to control how an array is serialized.)
You can achieve the same by changing your class structure to
public class Application
{
public string AppName;
public string UpdateDetail;
};
public class Pmsp_Update
{
public string OldVersion;
public string NewVersion;
public Application[] Applications;
};
<Applications> element will be added automatically for array property, so you don't need Applications class.

C# Serialize an object with a list of objects in it

In C# if I serialize an object that has a list of objects in it will it also serialize the list?
Example
public class Move {
public string MoveName {get; set;}
public List<Tag> oTags = new List<Tag>;
}
public class Tag {
public string TagName {get; set;}
}
If I serialize move will all the tags stored in move get serialized as well? Also if it will not serialize the list how would I go about making it do that?
<Move>
<MoveName>name</MoveName>
<Tag>Value</Tag>
...
</Move>

Yes, using the XmlSerializer it will serialize a List<T> so long as T (or in your case Tag) is serializable.
Move move = new Move { MoveName = "MyName" };
move.oTags.Add(new Tag { TagName = "Value1" } );
move.oTags.Add(new Tag { TagName = "Value2" } );
move.oTags.Add(new Tag { TagName = "Value3" } );
StringBuilder output = new StringBuilder();
var writer = new StringWriter(output);
XmlSerializer serializer = new XmlSerializer(typeof(Move));
serializer.Serialize(writer, move);
Console.WriteLine(output.ToString());
This outputs using your current class structure as:
<?xml version="1.0" encoding="utf-16"?>
<Move xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<oTags>
<Tag>
<TagName>Value1</TagName>
</Tag>
<Tag>
<TagName>Value2</TagName>
</Tag>
<Tag>
<TagName>Value3</TagName>
</Tag>
</oTags>
<MoveName>MyName</MoveName>
</Move>
I'll see if I can find a way to match your current XML schema, but you can look up how to apply XmlAttributes and play around with it yourself.
EDIT:
If you change your class declaration to use the following XmlAttributes, you will achieve the exact XML schema as in your example:
public class Move
{
[XmlElement(Order = 1)]
public string MoveName {get; set;}
[XmlElement(Order = 2, ElementName = "Tags")]
public List<Tag> oTags = new List<Tag>();
}
public class Tag
{
[XmlText]
public string TagName {get; set;}
}
Which when serialized will produce:
<?xml version="1.0" encoding="utf-16"?>
<Move xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<MoveName>MyName</MoveName>
<Tags>Value1</Tags>
<Tags>Value2</Tags>
<Tags>Value3</Tags>
</Move>

Are you sure that your class Declarations are right in your Question ?
you are just declaring Public Move, It should be Public class Move
Try this code
XmlSerializer serializer = new XmlSerializer(typeof(YourClass));
In Your case
Move m = new Move();
m.oTags.Add(new Tag() { TagName = "X" });
m.oTags.Add(new Tag() { TagName = "XX" });
XmlSerializer x = new XmlSerializer(typeof(Move));
System.IO.Stream s;
var xmlwriter = System.Xml.XmlWriter.Create("C:\\MXL.txt");
x.Serialize(xmlwriter, m);
OutPut
<?xml version="1.0" encoding="utf-8"?>
<Move xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<oTags>
<Tag>
<TagName>X</TagName>
</Tag>
<Tag>
<TagName>XX</TagName>
</Tag>
</oTags></Move>

By default, no it won't, since the items within the list may not be serializable.
If they are, then you may find the following page userful:
XML Serialize generic list of serializable objects

How to create XML with multiple namespace attributes in C#

How can I generate, for example, this XML in C#
<?xml version='1.0'?>
<oneshot xmlns='http://www.w3.org/2002/xforms' xmlns:dm='http://mobileforms.foo.com/xforms' xmlns:h='http://www.w3.org/1999/xhtml' xmlns:xsd='http://www.w3.org/2001/XMLSchema'>
<dm:form_namespace>Foo</dm:form_namespace>
<Days>6</Days>
<Leave_Type>Option 3</Leave_Type>
</oneshot>
I'm specifically struggling with the xmlns:dm declaration. Any ideas?

Your best bet (read: minimal amount of hacks) is probably going to be a custom IXmlSerializable implementation; you can get part-way to what you want via combinations of XmlRootAttribute, XmlElementAttribute, etc, like so:
[Serializable]
[XmlRoot("oneshot")]
public class OneShot
{
[XmlElement("form_namespace", Namespace="http://mobileforms.foo.com/xforms")]
public string FormNamespace {get; set;}
[XmlElement("Days")]
public int Days {get; set;}
[XmlElement("Leave_Type")]
public string LeaveType {get; set;}
Which will generate something like:
<?xml version="1.0" encoding="utf-16"?>
<oneshot xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<form_namespace xmlns="http://mobileforms.foo.com/xforms">Foo</form_namespace>
<Days>6</Days>
<Leave_Type>Option 3</Leave_Type>
</oneshot>
But if you implement IXmlSerializable, you have full control:
public class OneShot : IXmlSerializable
{
public string FormNamespace {get; set;}
public int Days {get; set;}
public string LeaveType {get; set;}
#region IXmlSerializable
public void WriteXml (XmlWriter writer)
{
writer.WriteStartElement("oneshot");
writer.WriteAttributeString("xmlns", null, "http://www.w3.org/2002/xforms");
writer.WriteAttributeString("xmlns:dm", null, "http://mobileforms.foo.com/xforms");
writer.WriteAttributeString("xmlns:h", null, "http://www.w3.org/1999/xhtml");
writer.WriteAttributeString("xmlns:xsd", null, "http://www.w3.org/2001/XMLSchema");
writer.WriteElementString("dm:form_namespace", null, FormNamespace);
writer.WriteElementString("Days", Days.ToString());
writer.WriteElementString("Leave_Type", LeaveType);
writer.WriteEndElement();
}
public void ReadXml (XmlReader reader)
{
// populate from xml blob
}
public XmlSchema GetSchema()
{
return(null);
}
#endregion
}
Which gives you:
<?xml version="1.0" encoding="utf-16"?>
<OneShot>
<oneshot xmlns="http://www.w3.org/2002/xforms" xmlns:dm="http://mobileforms.foo.com/xforms" xmlns:h="http://www.w3.org/1999/xhtml" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<dm:form_namespace>Foo</dm:form_namespace>
<Days>6</Days>
<Leave_Type>Option 3</Leave_Type>
</oneshot>
</OneShot>

One way to write XML with nodes in different namespaces is to use 4-argument version of XmlWriter.WriteElementString to explicitly specify namespace and prefixes the way you want:
var s = new StringWriter();
using (var writer = XmlWriter.Create(s))
{
writer.WriteStartElement("oneshot", "http://www.w3.org/2002/xforms");
writer.WriteElementString("dm", "form_namespace",
"http://mobileforms.foo.com/xforms","Foo");
// pick "http://www.w3.org/2002/xforms" by default for Days node
writer.WriteElementString("Days", "6");
// or you can explicitly specify "http://www.w3.org/2002/xforms"
writer.WriteElementString("Leave_Type",
"http://www.w3.org/2002/xforms", "Option 3");
writer.WriteEndElement();
}
Console.Write(s.ToString());
Note that your sample XML defines more prefixes than are used in the XML. If your requirement is to produce "text identical XML" (vs. identical from XML point of view, but not necessary represented with identical text) you may need to put more effort in adding namespace prefixes and xmlns attributes in places you need.
Note 2: creating XML object first (XDocument for modern/LINQ way, or XmlDocument if you like DOM more) may be easier approach.

Try using the XAML serializer from .NET 4.0+'s assembly System.Xaml.
You may need to add attributes to mark properties as content instead of XML attributes.

Thanks, all, for the help! It was a combination of two of the above answers that did it for me. I'm going to set the one that suggested the IXmlSerializable approach as that was the majority of the solution.
I had to declare the XMLRoot tag on the class name, remove WriteStartElement and WriteEndElement, and then use the four parameter declaration.
This is the class that worked in the end:
[Serializable]
[XmlRoot("oneshot")]
public class LeaveRequestPush : IXmlSerializable
{
public string FormNamespace { get; set; }
public int Days { get; set; }
public string LeaveType { get; set; }
#region IXmlSerializable
public void WriteXml(XmlWriter writer)
{
writer.WriteElementString("dm", "form_namespace", "http://mobileforms.devicemagic.com/xforms", FormNamespace);
writer.WriteElementString("Days", Days.ToString());
writer.WriteElementString("Leave_Type", LeaveType);
}
}
public void ReadXml (XmlReader reader)
{
// populate from xml blob
}
public XmlSchema GetSchema()
{
return(null);
}
Again, thanks all for the combined efforts. I would not have got this one by myself!

This code does the trick!
public void WriteXml(XmlWriter writer)
{
const string ns1 = "http://firstline.com/";
const string xsi = "http://www.w3.org/2001/XMLSchema-instance";
writer.WriteStartElement("myRoot", ns1);
writer.WriteAttributeString("SchemaVersion", "1.0");
writer.WriteAttributeString("xmlns", "xsi", "http://www.w3.org/2000/xmlns/", xsi);
writer.WriteAttributeString("xsi", "schemaLocation", xsi, ns1 + " schema1.xs");
writer.WriteStartElement("element1", ns1);
writer.WriteElementString("test1", ns1, "test value");
writer.WriteElementString("test2", ns1, "value 2");
writer.WriteEndElement();
writer.WriteEndElement();//to close classname that has root xml
}
Xml with multiple awesome namespaces!
<?xml version="1.0" encoding="utf-16"?>
<myClassNameWhereIXmlSerializableIsImplemented>
<myRoot SchemaVersion="1.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://firstline.com/ schema1.xs" xmlns="http://firstline.com/">
<element1>
<test1>test value</test1>
<test2>value 2</test2>
</element1>
</myRoot>
</myClassNameWhereIXmlSerializableIsImplemented>
There is something confusing about this line
writer.WriteAttributeString("xmlns", "xsi", "http://www.w3.org/2000/xmlns/", xsi);
if you give a random url instead of "http://www.w3.org/2000/xmlns/" , it will fail. The url that appear in xml is actually from "xsi" variable.
One more example to prove the point
writer.WriteAttributeString("xml", "base", "http://www.w3.org/XML/1998/namespace", base1);
where base1 = "<custom url>"
and if you want to output with a prefix like this <d:test1>somevalue<\d:test1> then writer.WriteElementString("d","test1", ns1, "somevalue"); if ns1 is not defined above then it will be added in xml output.
but for
<d:test1>
<blah>...
<\d:test1>
StartElement is needed writer.WriteStartElement("test1", ns1); to be closed when needed with writer.WriteEndElement();

C# deserialize XML

I have problem with deserialize document to object using XmlSerializer class.
Code my function for deserialize:
static public TYPE xmlToObject<TYPE>( string xmlDoc ) {
MemoryStream stream = new MemoryStream();
byte[] xmlObject = ASCIIEncoding.ASCII.GetBytes( xmlDoc );
stream.Write( xmlObject, 0, xmlObject.Length );
stream.Position = 0;
TYPE message;
XmlSerializer xmlSerializer = new XmlSerializer( typeof( TYPE ) );
try {
message = (TYPE)xmlSerializer.Deserialize( stream );
} catch ( Exception e ) {
message = default( TYPE );
} finally {
stream.Close();
}
return message;
}
And I have class:
public class Test {
public int a;
public int b;
}
And deserialize:
string text = File.ReadAllText( "blue1.xml" );
Test a = XmlInterpreter.xmlToObject<Test>( text );
Ok, when I read file like this:
<?xml version="1.0" encoding="UTF-8"?>
<Test>
<a>2</a>
<b>5</b>
</Test>
everything is OK. But like this:
<?xml version="1.0" encoding="UTF-8"?>
<Test>
<a>2</a>
<b></b>
</Test>
is wrong because
<b></b>
is empty and conversion into int is impossible.
How can I solve this? For example I want in this context that b will be not declared.
What when my class is:
public class Test {
public enum Pro {
VALUE1,
VALUE2
}
public Pro p1;
}
And I want accept xmlDocument, where field p1 is empty.

I expect that first example is just some type because it has empty b as well. First of all not every XML can be deserialized to object. Especially empty elements are dangerous and should not be used. If you want to express that b is not defined then do not include it in XML file:
<?xml version="1.0" encoding="UTF-8"?>
<Test>
<a>2</a>
</Test>
or make your b property nullable:
public class Test {
public int a;
public int? b;
}
and define XML as:
<?xml version="1.0" encoding="UTF-8"?>
<Test xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<a>2</a>
<b xsi:nil="true" />
</Test>
Generally if you want to use deserialization try to first use serialization to understand how must a valid XML look like.

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