I am using XmlSerializer in c# to serialize a class instance to xml. By default, if I serialize the instance of following class:
public class XmlTest
{
public bool b1;
}
the bool field is represented as <b1>false</b1>
I have specific requirement that the value of bool fields be represented as elements as in <false> and <true> instead of text content. I have similar requirements for enum fields as well.
I have tried using attributes that control XML serialization but couldn't find one that meets my requirement. I am fairly new to c# and was wondering the best way to achieve this.
You can't do that with the XML Serializer. You can use LINQ to XML instead:
public XElement Serialize(XmlTest t){
return new XElement("XmlTest",
new XElement(t.b1 ? "true" : "false"));
}
One hint on using LINQ to XML in an code generation setting: XElement has a constructor that looks very simple:
public XElement(
XName name,
Object content
)
but that content parameter can be almost anything. That includes
Any type that implements ToString
Any type that implements IEnumerable
So, for example:
XElement xmlTree2 = new XElement("Root",
from el in xmlTree1.Elements()
where((int)el >= 3 && (int)el <= 5)
select el
);
could produce
<Root>
<Child3>3</Child3>
<Child4>4</Child4>
<Child5>5</Child5>
</Root>
Related
I have an object that I serialize into an XML file. Everything works as expected, but I'm wanting to add a Version attribute to the root element.
What's the best way to do this?
Here's an example of how I'm serializing:
MyProgram newProgram = new MyProgram()
{
ValueA = "A value.",
ValueB = "B value.",
ValueC = "C value."
};
XmlSerializer xmlSerializer = new XmlSerializer(typeof(MyProgram));
StreamWriter streamWriter = new StreamWriter(fileName);
xmlSerializer.Serialize(streamWriter, newProgram);
streamWriter.Close();
Right now, my XML looks something like this:
<MyProgram>
<ValueA>A value.</ValueA>
<ValueB>B value.</ValueB>
<ValueC>C value.</ValueC>
</MyProgram>
But I'd like to have this:
<MyProgram Version="1.0">
<ValueA>A value.</ValueA>
<ValueB>B value.</ValueB>
<ValueC>C value.</ValueC>
</MyProgram>
Thanks!
First
Modify your XML to be like this, assuming you have a concrete class and not an anonymous one
[XmlRoot("MyProgram")]//sepcifies the name of the root element
public class MyProgram
{
[XmlAttribute("Version")]//name not required unless you want to change output to something different
public string Version{get;set;}
[XmlElement("ValueA")]//again, name not required if the name is the same
public ValueA ValueA{get;set;}
....
}
Then creating the MyProgram class as you specified will give you the desired output, also note that you might need to add XML tags to the ValueA/B/C classes if the end result is not as desired.
The second
Serialize the XML data to a string, and use simple Regex/String manipulation to insert the desired value and then save the string to the desired location
Third
You can either use XElement to query your XML string /Create it and then set the Version attribute
XElement x = XElement.Load("Your XML location");
var yourRoot = x.Descendants("MyProgram").FirstOrDefaul();
yourRoot.SetAttributeValue("Version","1.0");
yourRoot.Save("Your XML location");
I have some xml that looks like this:
<?xml version="1.0" encoding="UTF-8"?>
<response>
<video key="8bJ8OyXI">
<custom>
<legacyID>50898311001</legacyID>
</custom>
<date>1258497567</date>
<description>some description</description>
<duration>486.20</duration>
<md5>bc89fde37ef103db26b8a9d98065d006</md5>
<mediatype>video</mediatype>
<size>99416259</size>
<sourcetype>file</sourcetype>
<status>ready</status>
<views>0</views>
</video>
</response>
I am using XmlSerializer to serialize the xml to class objects, and would prefer to stick with it if possible since everything else works just fine. The node custom is just custom metadata added to the video, and pretty much anything could potentially end up in there (only strings, just a name and value). I used xsd.exe to generate class objects from my xml, which generated a unique class for the <custom> tag with just one ulong property for the legacyID value. The thing is, potentially any arbitrary number of values could be there and I can't and don't need to account for them all (but I may need to read particular values later).
Is it possible to set up the Video.Custom property in my class so that the serializer can deserialize those values into say something like a Dictionary<string, string>? I don't need type information for those particular values, saving the node names + values are more than enough for my purposes.
You can handle UnknownElement event and there deserialize custom element to your dictionary
serializer.UnknownElement += (s, e) =>
{
if (e.Element.LocalName == "custom" && e.ObjectBeingDeserialized is Video)
{
Video video = (Video)e.ObjectBeingDeserialized;
if (video.Custom == null)
{
video.Custom = new Dictionary<string, string>();
}
foreach (XmlElement element in e.Element.OfType<XmlElement>())
{
XmlText text = (XmlText)element.FirstChild;
video.Custom.Add(element.LocalName, text.Value);
}
}
};
I'm using
List<EFacebook> facebooks = BFacebook.ReadFacebookFriends(user.EProviders
.Where(i => i.ProviderType == EProvider.EnumProviderType.Facebook)
.First().Token);
StringBuilder xml = new StringBuilder();
foreach (EFacebook i in facebooks)
{
xml.AppendFormat("<id>{0}</id>", i.id);
}
Can anybody suggest a better code to serialize each i.id into an XML string?
Edit:
The facebook object has close to 20 properties. If I XmlSerializer all 20 properties are serialized into the XML. I just need the id column.
You might want to take a look at XML Serialization already built into the .NET Framework.
You can use code similar to the following to serialize the object:
MySerializableClass myObject = new MySerializableClass();
// Insert code to set properties and fields of the object.
XmlSerializer mySerializer = new
XmlSerializer(typeof(MySerializableClass));
// To write to a file, create a StreamWriter object.
StreamWriter myWriter = new StreamWriter("myFileName.xml");
mySerializer.Serialize(myWriter, myObject);
myWriter.Close();
See: How to serialize
You can flag properties to be ignored using the XmlIgnore attribute as shown below:
public class Group
{
// The XmlSerializer ignores this field.
[XmlIgnore]
public string Comment;
// The XmlSerializer serializes this field.
public string GroupName;
}
See XMLIgnore
XmlSerializer xs = new XmlSerializer(typeof(int[]));
xs.Serialize(stream,facebooks.Select(x=>x.id).ToArray())
I would use Linq To Xml to create the Xml Tree structure
See for an example: Linq To Xml
If you're just saving the id values into an xml string then I wouldn't say that you're 'serializing' the objects.
Whenever working with XML it's much nicer to use an XML library than to wrangle with text. One obvious reason is that it guarantees your XML will be well-formed.
I'd do something like this:
List<EFacebook> facebooks = GetFriends();
var facebookIds = facebooks.Select(f => new XElement("id", f.id));
var facebookXml = new XElement("facebookIds", facebookIds);
Which will give you XML like
<facebookIds>
<id>1</id>
<id>2</id>
</facebookIds>
I currently load an XML file into a list objects using code like this
XDocument xmlDoc = XDocument.Load(path);
List<ImportDefinition> importDefinitions = xmlDoc.Descendants("Root").Select(xElem => (ImportDefinition)xElem).ToList();
return importDefinitions;
This list of objects contains nested objects and each one has an operator for parsing the XML into the correct form like this
public static explicit operator Rules(XElement xElem)
{
try
{
return new Rules()
{
FileNameRegEx = (string)xElem.Element("FileNameRegEx"),
FileExtension = (string)xElem.Element("FileExtension")
};
}
catch (Exception ex)
{
return null;
}
This works fine for loading the XML. I now want to save this list of objects back to XML after some edits have been made.
I was hoping something like this would work
XElement xml = new XElement("Root",
from p in ObjectList
select new XElement("File",RootObject
));
}
xml.Save("C:\\temp\\newimport.xml");
However this just seems to output this
<?xml version="1.0" encoding="utf-8"?>
<Root>
<File>MyNamespace.RootObject</File>
<File>MyNamespace.RootObject</File>
</Root>
It looks like its not using the custom operators it uses when loading the files to work out the format to save in. Whats the best way to save this data back to XML to the same format it was in when I read it?
Well for one thing you've only shown us the operator for parsing from an XElement... but even so, you're obviously explicitly calling that in your LINQ expression. If you want the equivalent when building XML, you'll need to be explicit there too:
XElement xml = new XElement("Root",
from p in ObjectList
select new XElement("File", (XElement) p));
Personally I'd use methods instead of operators - ToXElement() and FromXElement() - I think it's clearer that way. ToXElement would be an instance method; FromXElement would be a static method. This is a pattern I've used many times, and it's always worked fine.
I am creating an application which requires to convert c# object to XML.
I am using XML Serializer class to achieve this. Here is the code snippet:
public class Anwer
{
public int ID { get; set; }
public string XML { get; set; }
public Anwer(int ID, string XML)
{
this.ID = ID;
this.XML = XML;
}
public Anwer() { }
}
Here is the main function:
string AnswerXML = #"<Answer>1<Answer>";
List<Anwer> answerList = new List<Anwer>();
answerList.Add(new Anwer(1,AnswerXML));
AnswerXML = #"<Answer>2<Answer>";
answerList.Add(new Anwer(2, AnswerXML));
XmlSerializer x = new XmlSerializer(answerList.GetType());
x.Serialize(Console.Out, answerList);
The output is:
<?xml version="1.0" encoding="IBM437"?>
<ArrayOfAnwer xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="h
ttp://www.w3.org/2001/XMLSchema">
<Anwer>
<ID>1</ID>
<XML><Answer>1<Answer></XML>
</Anwer>
<Anwer>
<ID>2</ID>
<XML><Answer>2<Answer></XML>
</Anwer>
</ArrayOfAnwer>
In the above code '<' and '>' are getting replaced by '<' and '>';
How to avoid this?
I know string replace is one of the way, but I don't want to use it.
Thanks in advance.
You don't, basically. That's correctly serializing the object - the XML serializer doesn't want to have to deal with XML within strings messing things up, so it escapes the XML appropriately.
If you deserialize the XML later, you'll get back to the original object data.
If you're trying to build up an XML document in a custom fashion, I suggest you don't use XML serialization to start with. Either use LINQ to XML if you're happy to create elements etc explicitly, or if you really, really want to include arbitrary strings directly in your output, use XmlWriter.
If you could give us more information about the bigger picture of what you're trying to do, we may be able to suggest better alternatives - building XML strings directly is almost never a good idea.
XmlSerializer won't believe you that an element is xml unless you convince it, for example by exposing that property as an XmlDocument. Otherwise, it (correctly, IMO) always encodes such values. For example:
using System;
using System.Xml;
using System.Xml.Serialization;
public class Anwer
{
public int ID { get; set; }
public XmlDocument XML { get; set; }
public Anwer(int ID, string XML)
{
this.ID = ID;
XmlDocument doc = new XmlDocument();
doc.LoadXml(XML);
this.XML = doc;
}
public Anwer()
{ }
}
static class Program
{
static void Main()
{
var answer = new Anwer(123, "<Answer>2</Answer>");
var ser = new XmlSerializer(answer.GetType());
ser.Serialize(Console.Out, answer);
}
}
I am creating an application which requires to convert c# object to XML. I am using XML Serializer class to achieve this
If you're using the XML Serializer to do the work, then why the "XML" field where you're inserting hand-coded XML? Seems like you want something more like this (using your class name, though it looks like a misspelling):
public class Anwer
{
public int ID { get; set; }
public int Answer { get; set; }
}
..
List<Anwer> answerList = new List<Anwer>() {
new Anwer { ID=1, Answer=2 },
new Anwer { ID=2, Answer=3 },
};
XmlSerializer x = new XmlSerializer(answerList.GetType());
x.Serialize(Console.Out, answerList);
..
<ArrayOfAnwer ...>
<Anwer>
<ID>1</ID>
<Answer>2</Answer>
</Anwer>
...
Or if you actually want/need the Answer element to be nested in an XML element for some reason, you can alter your Anwer object to reflect that structure (as Oleg Kalenchuk suggests), or generate the XML yourself rather than using the serializer:
XElement xml = new XElement("AnwerList",
from anwer in anwerList select
new XElement("Anwer",
new XElement("ID", anwer.ID),
new XElement("XML",
new XElement("Answer", anwer.Answer)
)
)
);
Console.Out.WriteLine(xml);
<AnwerList>
<Anwer>
<ID>1</ID>
<XML>
<Answer>2</Answer>
</XML>
</Anwer>
...
I prefer the latter anyway, because it gives you more control.
You're assigning a string containing the < and > sign to the XML element so it is obvious that teh serializer would replace the < and > with entity references. Even if you're getting > in the text when you deserialise the XML you'll get the > in your text.
Create a new class AnswerXML with one integer "Answer" member
Change type of XML member to AnswerXML instead of string
Because '<' and '>' are characters used for the xml-structure itself, they are automatically htmlencoded. When you read it back in your app and deserialize it, the '<' and '>' should be converted back to '<' and '>'.
If your goal is otherwise, use htmldecode functionality.
If this don't help, just tell what exactly you want to do with the xml-data.