We Keep Coding

Saving object state using xml Serializer. Recommend approach for getting node name from property or hardcoded string?

We are trying to save state of our object using XML serializer. For discussion assume object to be like:
Class Program
{
public string Char1 {get; set;}
public XMLNode Serialize (XmlDocument doc)
{
var node = document.CreateElement("Mod")
node.SetAttribute("Char1", Char1.ToString());
}
}
Here we are getting the value of property Char1 and trying to write it in a node with name Char1.
Is it better to have the node name "Char1" be derived from Char1 property using reflection. But this could result in changing the XML document often when property name is changed.
If property name is changed and the string is not updated then the value in xml document will not match the context of that field.
What approach is preferable?
Please suggest if there is any other better approach to avoid magic strings while writing xml file.

I would prefer following way: Create a class which holds all your data you want wo serialize. Then create an instance of the XmlSerializer like this
xmlDocument = new XmlDocument();
using (var stringWriter = new StringWriter(CultureInfo.InvariantCulture))
{
using (var xmlTextWriter = new XmlTextWriter(stringWriter))
{
xmlTextWriter.Formatting = Formatting.Intented;
var xmlSerializer = new XmlSerializer(myObject.GetType());
xmlSerializer.Serialize(xmlTextWriter, myObject);
xmlDocument.PreserveWhitespace = true;
xmlDocument.LoadXml(stringWriter.ToString());
}
}

Parsing XML using C#, getting attribute value

I have the following (simplified) notepad file, which from what I understand is XML text:
<?xml version="1.0" encoding="utf-8"?>
<appSettings>
<add key="Active_01" value="1">
</add>
</appSettings>
I am trying to parse it using C#.
So far I have the following:
public class RFIDScanner
{
public void GetScannerConfigFile()
{
string File = ConfigurationManager.AppSettings["RFIDScannerConfiguration"];
XmlDocument doc = new XmlDocument();
doc.Load(File);
XmlNode node = doc.DocumentElement.SelectSingleNode("/appSettings");
String nodename = node.Name;
}
}
So far I know this is all correct, as:
nodename = appSettings
Which is as it should be.
My problem is, how do I retrieve the value "1" from the field "Active_01".
I now know that the node "add" is a child of the node "appSettings", and a trying to work out how to get the value stored in it.

Not sure if you wish to parse the '1' from the key Active_01, or get the 1 from the value. In Any case, you can use the following code:
public void GetScannerConfigFile()
{
string File = ConfigurationManager.AppSettings["RFIDScannerConfiguration"];
XmlDocument doc = new XmlDocument();
doc.Load(File);
var yourFile = doc.DocumentElement;
if (yourFile == null) return;
// Here you'll get the attribute key: key = Active_01 - which can be simply parsed for getting only the "1"
string key = yourFile.ChildNodes[0].Attributes["key"].Value;
// Here you'll get the number "1" from the value attribute.
string value = yourFile.ChildNodes[0].Attributes["value"].Value;
}

There are many ways, one is to use the XPath using the function you use above:
var value = doc.DocumentElement.SelectSingleNode("/appSettings/add/#value");
Another option is to use xml serialization:
You'd define classes as follows:
public class add
{
[XmlAttribute]
public string key;
[XmlAttribute]
public int value;
}
public class appSettings
{
public add add;
}
And then deserialize as follows:
var ser = new XmlSerializer(typeof(appSettings));
var xmlReader = new XmlTextReader(new StringReader(s));
appSettings settings = (appSettings) ser.Deserialize(xmlReader);
xmlReader.Close();
You can then get the values from settings

I have used this way in my code to add values to xml
may be it will help
var surveyTypeList = new XElement("SurveyTypes");
foreach (var item in modelData.SurveyTypeList)
{
if (item.IsSelected)
{
var surveyType = new XElement("SurveyType");
var id = new XElement("Id");
id.Add(item.Value);
// **var i= id.Value**
surveyType.Add(id);
surveyTypeList.Add(surveyType);
}
}
you can get value by var i= id.Value in your code;

XML Serialize C#

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>

C# object to XML

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 '&gt';
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.

Deserialize XML into a C# object

How can I desearlize the below CatalogProduct tags into my CatalogProduct object using C#?
<?xml version="1.0" encoding="UTF-8"?>
<CatalogProducts>
<CatalogProduct Name="MyName1" Version="1.1.0"/>
<CatalogProduct Name="MyName2" Version="1.1.0"/>
</CatalogProducts>
Note i don't have a CatalogProducts object so want to skip that element when pulling back the into to deserialize
Thanks

var xml = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>" +
"<CatalogProducts>" +
"<CatalogProduct Name=\"MyName1\" Version=\"1.1.0\"/>" +
"<CatalogProduct Name=\"MyName2\" Version=\"1.1.0\"/>" +
"</CatalogProducts>";
var document = XDocument.Parse(xml);
IEnumerable<CatalogProduct> catalogProducts =
from c in productsXml.Descendants("CatalogProduct")
select new CatalogProduct
{
Name = c.Attribute("Name").Value,
Version = c.Attribute("Version").Value
};

Just for your information, here's an example how to really serialize and deserialize an object:
private CatalogProduct Load()
{
var serializer = new XmlSerializer(typeof(CatalogProduct));
using (var xmlReader = new XmlTextReader("CatalogProduct.xml"))
{
if (serializer.CanDeserialize(xmlReader))
{
return serializer.Deserialize(xmlReader) as CatalogProduct;
}
}
}
private void Save(CatalogProduct cp)
{
using (var fileStream = new FileStream("CatalogProduct.xml", FileMode.Create))
{
var serializer = new XmlSerializer(typeof(CatalogProduct));
serializer.Serialize(fileStream, cp);
}
}

The canonical method would be to use the xsd.exe tool twice. First, to create a schema from your example XML as so:
xsd.exe file.xml will generate file.xsd.
Then:
xsd.exe /c file.xsd will generate file.cs.
File.cs will be the object(s) you can deserialize your XML from using any one of the techniques that you can easily find here, e.g. this.

Assuming your CatalogProduct object looks something like this:
public class CatalogProduct {
public string Name;
public string Version;
}
I think Linq to Xml will be the simplest and fastest way for you
var cps1 = new[] { new CatalogProduct { Name = "Name 1", Version = "Version 1" },
new CatalogProduct { Name = "Name 2", Version = "Version 2" } };
var xml = new XElement("CatalogProducts",
from c in cps1
select new XElement("CatalogProduct",
new XAttribute("Name", c.Name),
new XAttribute("Version", c.Version)));
// Use the following to deserialize you objects
var cps2 = xml.Elements("CatalogProduct").Select(x =>
new CatalogProduct {
Name = (string)x.Attribute("Name"),
Version = (string)x.Attribute("Version") }).ToArray();
Please note that .NET offers true object graph serialization which I have not shown

Without "CatalogProduct" object i think it's very difficult, maybe with the dynamic type of .net 4.0 it's possible, but i'm not sure.
The only way i know, is to utilize the XmlSerializer class with Deserialize method, but you need the object CatalogProduct.
I hope the following link is useful:
Link