Develop Reference

How can I be notified if I deserialize XML to C# and there's no corresponding C# property?

I'm working with some third party XML that has no formally defined schema, only example XML. I have several thousand XML files from this third party. There is no guarantee that every possible element lies within one or more of these files. The third party service could send me a new file with a new element!
I can view these files and reverse engineer types relatively easily.
For example:
<MyObject>
<MyProperty>Some value</MyProperty>
</MyObject>
Could deserialize to
public class MyObject
{
public string MyProperty { get; set; }
}
No problems so far.
But what if I attempt to deserialize this:
<MyObject>
<MyProperty>Some value</MyProperty>
<MyOtherProperty>Some value</MyOtherProperty>
</MyObject>
into my class above? I want it to throw an exception, so I can be notified that my class does not accommodate MyOtherProperty.
Is there a way to do this?
I'd like to share the code I wrote using the accepted answer. Using the below utility method, I can deserialize without checks for unknown stuff, and with checks, by setting strict=true.
I hope readers find this useful!
public static T XmlDeserialize<T>(string xml, bool strict = false)
{
using (var stringReader = new StringReader(xml))
{
using (var xmlTextReader = new XmlTextReader(stringReader))
{
var xmlSerializer = new XmlSerializer(typeof(T));
if (strict)
{
var options = new XmlDeserializationEvents();
options.OnUnknownElement += (sender, args) =>
{
throw new XmlDeserializationException(xml, $"Unexpected Element {args.Element.LocalName} on line {args.LineNumber}.");
};
options.OnUnknownAttribute += (sender, args) =>
{
throw new XmlDeserializationException(xml, $"Unexpected Element: {args.Attr.LocalName} on line {args.LineNumber}.");
};
options.OnUnknownNode += (sender, args) =>
{
throw new XmlDeserializationException(xml, $"Unexpected Element: {args.LocalName} on line {args.LineNumber}.");
};
return (T)xmlSerializer.Deserialize(xmlTextReader, options);
}
return (T)xmlSerializer.Deserialize(xmlTextReader);
}
}
}
And that exception class I'm throwing looks like this:
public class XmlDeserializationException : Exception
{
public string Xml { get; private set; }
public XmlDeserializationException(
string xml, string message) : base (message)
{
Xml = xml;
}
}
I can check my logs and look up the line number in the actual xml. Works perfectly. Thanks, pfx.

The XmlSerializer has a Deserialize overload allowing to pass in an options element by which to hook to some events; eg. OnUnknownElement.
XmlDeserializationEvents options = new XmlDeserializationEvents();
options.OnUnknownElement += (sender, args) => {
XmlElement unknownElement = args.Element;
// throw an Exception with this info.
} ;
var o = serializer.Deserialize(xml, options) as MyObject;
The OnUnknowElement takes nested elements into account.
With the classes below
public class MyObject
{
public string MyProperty { get; set; }
public MyOtherObject Other { get; set; }
}
public class MyOtherObject
{
public string SomeProperty { get; set; }
}
and the following xml
<MyObject>
<MyProperty>Some value</MyProperty>
<Other>
<SomeProperty>...</SomeProperty>
<UFO>...</UFO>
</Other>
</MyObject>
The OnUnknowElement handler will trigger for the UFO element.

One way of doing so would be to use your current object model and create an XSD out of it. You can then check new files against that XSD and throw if it doesn't validate.

Extend your class with an XmlAnyElement container.
Any unknown elements will end up in that array.
After deserialization check whether that array is empty.
public class MyObject
{
[XmlAnyElement]
public XmlElement[] UnknownElements;
public string MyProperty { get; set; }
}

Unusual XML Format I Must Iterate Through

I need to iterate through some XML that has an unusual format to it. It looks like this:
<Baseball>
<Player playerID="123" playerName="John Smith" playerBats="Right"/>
<position positionID="1b" positionCode="abc" counter="3"/>
<position positionID="2b" positionCode="def" counter="2"/>
</Player>
</Baseball>
I cannot change this format that is given to me. I need to iterate through every line and different pieces get pulled and go to different places. I will be doing the code in C#. Ideas? Thank you!

Assuming your input XML actually IS valid XML, this is the pattern I use for this type of thing.
Your example XML isn't valid because Player is both self closing, and has an explicit closing tag. I've adjusted it to my best guess of what it should look like.
If that really is the XML you have to deal with, XmlDocument.LoadXml will throw an error. You will need to find some other way to deal with the malformed data, perhaps pre-processing the data to remove the / on the Player element so it is no longer self closing.
The basic pattern is that there is a class for each element in the XML. Each class has a static function FromXml that accepts an XmlElement for the matching element in the XML. FromXML is responsible for reading, parsing, and populating its properties from attributes. Child elements are processed by calling FromXml on their associated classes.
class Program
{
static void Main(string[] args)
{
string xml =
#"<Baseball>
<Player playerID=""123"" playerName=""John Smith"" playerBats=""Right"">
<position positionID=""1b"" positionCode=""abc"" counter=""3""/>
<position positionID=""2b"" positionCode=""def"" counter=""2""/>
</Player>
</Baseball>";
var document = new XmlDocument();
document.LoadXml(xml);
var players = new List<Player>();
foreach (XmlElement baseballElement in document.SelectNodes("Baseball"))
{
foreach (XmlElement playerElement in baseballElement.SelectNodes("Player"))
{
players.Add(Player.FromXml(playerElement));
}
}
Console.ReadLine();
}
}
public class Player
{
public static Player FromXml(XmlElement PlayerElement)
{
var player = new Player();
player.PlayerId = int.Parse(PlayerElement.GetAttribute("playerID"));
player.PlayerName = PlayerElement.GetAttribute("playerName");
player.PlayerBats = PlayerElement.GetAttribute("playerBats");
foreach (XmlElement positionElement in PlayerElement.SelectNodes("position"))
{
player.Positions.Add(Position.FromXml(positionElement));
}
return player;
}
public int PlayerId { get; set; }
public string PlayerName { get; set; }
public string PlayerBats { get; set; }
private List<Position> _positions = new List<Position>();
public List<Position> Positions
{
get { return _positions; }
}
}
public class Position
{
public static Position FromXml(XmlElement positionElement)
{
var position = new Position();
position.PositionId = positionElement.GetAttribute("positionID");
position.PositionCode = positionElement.GetAttribute("positionCode");
position.Counter = int.Parse(positionElement.GetAttribute("counter"));
return position;
}
public string PositionId { get; set; }
public string PositionCode { get; set; }
public int Counter { get; set; }
}
This will create a list of Player each of which contains a list of Position, all populated from the XML.
I also haven't done any kind of error checking on the input XML. If any attributes are missing or in the wrong format, it will throw an error.

how to remove default namespaces and add custom namespace in root tag of xml using C#?

While creating xml from C# class I getting some default namespaces(xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema") in root tag (Order) like below. but, I want to remove those default namespaces and I need the following namespace in the root tag (Order xmlns="http://example.com/xml/1.0").
how to remove those default namespaces and replace in c# code. thanks in advance.
<?xml version="1.0"?>
<Order xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<Number Type="mobile">9999999999</Number>
<TrackStartDateTime>2015-05-30 11:00 ET</TrackStartDateTime>
<Notifications>
<Notification>
<PartnerMPID>99999999</PartnerMPID>
<IDNumber>L563645</IDNumber>
<TrackDurationInHours>120</TrackDurationInHours>
<TrackIntervalInMinutes>240</TrackIntervalInMinutes>
</Notification>
</Notifications>
<Carrier>
<Dispatcher>
<DispatcherName>?</DispatcherName>
<DispatcherPhone>0</DispatcherPhone>
<DispatcherEmail>?</DispatcherEmail>
</Dispatcher>
</Carrier>
</Order>
I have used following C# classes.
[XmlRoot("Order")]
public class Order
{
[XmlElement("Number")]
public Number Number;
[XmlElement("TrackStartDateTime")]
public string TrackStartDateTime;//TODO - need to check
[XmlElement("Notifications")]
public Notifications Notifications;//TODO - notification tag should come inside Notifications tag
[XmlElement("Carrier")]
public Carrier Carrier;
public Order() {
Number = new Number();
Notifications = new Notifications();
Carrier = new Carrier();
TripSheet = new TripSheet();
}
}
public class Number
{
[XmlAttribute("Type")]
public string Type;
[XmlText]
public Int64 Value;
}
public class Notifications {
[XmlElement("Notification")]
public List<Notification> Notification;
public Notifications() {
Notification = new List<Notification>();
}
}
public class Notification
{
[XmlElement("PartnerMPID")]
public string PartnerMPID { get; set; }
[XmlElement("IDNumber")]
public string IDNumber { get; set; }
[XmlElement("TrackDurationInHours")]
public int TrackDurationInHours { get; set; }
[XmlElement("TrackIntervalInMinutes")]
public int TrackIntervalInMinutes { get; set; }
}
public class Carrier
{
[XmlElement("Name")]
public string Name;
[XmlElement("Dispatcher")]
public Dispatcher Dispatcher;
public Carrier() {
Dispatcher = new Dispatcher();
}
}
public class Dispatcher
{
[XmlElement("DispatcherName")]
public string DispatcherName;
[XmlElement("DispatcherPhone")]
public Int64 DispatcherPhone;
[XmlElement("DispatcherEmail")]
public string DispatcherEmail;//conform format for email
}
and I have taken the new instance of Order Class and for testing purpose, I have hard-coded values for the each fields and I have used the following code for the creating xml from the C# class.
public string CreateXML(Order order)
{
XmlDocument xmlDoc = new XmlDocument();
XmlSerializer xmlSerializer = new XmlSerializer(typeof(Order));
// Creates a stream whose backing store is memory.
using (MemoryStream xmlStream = new MemoryStream())
{
xmlSerializer.Serialize(xmlStream, order);//,ns
xmlStream.Position = 0;
//Loads the XML document from the specified string.
xmlDoc.Load(xmlStream);
return xmlDoc.InnerXml;
}
}
I am not sure its a right approach for creating xml from C# classes. Please guide me to get the following xml output from c# class.
<?xml version="1.0"?>
<Order xmlns="http://example.com/xml/1.0" >
<Number Type="mobile">9999999999</Number>
<TrackStartDateTime>2015-05-30 11:00 ET</TrackStartDateTime>
<Notifications>
<Notification>
<PartnerMPID>99999999</PartnerMPID>
<IDNumber>L563645</IDNumber>
<TrackDurationInHours>120</TrackDurationInHours>
<TrackIntervalInMinutes>240</TrackIntervalInMinutes>
</Notification>
</Notifications>
<Carrier>
<Dispatcher>
<DispatcherName>?</DispatcherName>
<DispatcherPhone>0</DispatcherPhone>
<DispatcherEmail>?</DispatcherEmail>
</Dispatcher>
</Carrier>
</Order>

Here is a way to do it...
Just create a new XDocument and set the namespace that you want on it and transplant the original xml descendant into it, like so:
var xml = "<?xml version=\"1.0\"?><Order xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\"><Number Type=\"mobile\">9999999999</Number></Order>";
var xdoc = XDocument.Parse(xml);
var ns = XNamespace.Get("http://example.com/xml/1.0");
var xdoc2 = new XDocument(new XDeclaration("1.0", null, null),
new XElement(ns + "Order", xdoc.Root.Descendants()));
See here for working sample: https://dotnetfiddle.net/JYCL95

For this case it should be sufficient to simply add a null namespace to the XMLRoot decoration used on your class definition.
[XmlRoot("Order", Namespace = null)]
public class Order
{
[XmlElement("Number")]
public Number Number;
[XmlElement("TrackStartDateTime")]
public string TrackStartDateTime;
[XmlElement("Notifications")]
public Notifications Notifications;
[XmlElement("Carrier")]
public Carrier Carrier;
The serializer should do the rest.

Cannot deserialize XML into a list using XML Deserializer

This follows on from my previous question Serialize list of interfaces using XML Serialization
public class MeterWalkOrder
{
public MeterWalkOrder()
{
Meters = new List<IMeter>();
}
public String Name { get; set; }
[XmlIgnore]
public List<IMeter> Meters { get; set; }
[XmlArrayItem(ElementName = "Meter")]
[XmlArray(ElementName = "Meters")]
public List<Meter> SerializableMeters
{
get
{
return Meters.Cast<Meter>().ToList();
}
set
{
Meters = new List<IMeter>(value);
}
}
}
public interface IMeter {
int MeterID { get; set; }
}
public class Meter : IMeter {
public int MeterID { get; set; }
public string SerialNumber { get; set; }
}
}
I am using the extension method below to deserialize the XML back into my object (ideally I would prefer the extension method to be off of object, but I not too comfortable with extension methods so I have left like this for now)...
public static class SerializationExtensions
{
public static T LoadFromXML<T>(this string xmlString)
{
T returnValue = default(T);
XmlSerializer serial = new XmlSerializer(typeof(T));
StringReader reader = new StringReader(xmlString);
object result = serial.Deserialize(reader);
if (result != null && result is T)
{
returnValue = ((T)result);
}
reader.Close();
return returnValue;
}
....However, when I give the XML below....
<?xml version="1.0"?>
<MeterWalkOrder xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<Name>Red Route</Name>
<Meters>
<Meter>
<MeterID>1</MeterID>
<SerialNumber>12345</SerialNumber>
</Meter>
<Meter>
<MeterID>2</MeterID>
<SerialNumber>SE</SerialNumber>
</Meter>
</Meters>
</MeterWalkOrder>
No meters are populated?
Does anyone know what could cause this problem? The XML is valid and SerializeableMeters is simply a property that reads from and writes to Meters but casting it as a concrete class due to the known issues with using interfaces in serialization

The problem is that XmlSerializer deserializes a property referring to a class implementing IList<T> in the following way:
It calls the getter to get the list. If null, it allocates a list and sets it via the setter. It holds onto the list in some local variable while reading it.
It deserializes each list element, and adds it to the list it is holding.
And that's it. It never calls the containing class's list property setter afterwards.
You can verify this by replacing your List<Meter> with an ObservableCollection<Meter>, and setting a debug listener for when the collection changes:
[XmlArrayItem(ElementName = "Meter")]
[XmlArray(ElementName = "Meters")]
public ObservableCollection<Meter> SerializableMeters
{
get
{
Debug.WriteLine("Returning proxy SerializableMeters");
var list = new ObservableCollection<Meter>(Meters.Cast<Meter>());
list.CollectionChanged += new System.Collections.Specialized.NotifyCollectionChangedEventHandler(list_CollectionChanged);
return list;
}
set
{
Debug.WriteLine("Setting proxy SerializableMeters");
Meters = new List<IMeter>(value.Cast<IMeter>());
}
}
static void list_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
{
var collection = (IList<Meter>)sender;
Debug.WriteLine("Proxy collection changed to include : ");
foreach (var item in collection)
Debug.WriteLine(" " + item.ToString());
}
Doing so, you'll see the following debug output:
Returning proxy SerializableMeters
Returning proxy SerializableMeters
Returning proxy SerializableMeters
Returning proxy SerializableMeters
Proxy collection changed to include :
Meter: 1, 12345
Proxy collection changed to include :
Meter: 1, 12345
Meter: 2, SE
As you can see, the list is never set back.
Luckily, there's an easy alternative. If you return a proxy array instead of a proxy List, XmlSerializer will allocate the array itself, populate it, and set it via the setter -- which is just what you want!
[XmlArrayItem(ElementName = "Meter")]
[XmlArray(ElementName = "Meters")]
public Meter [] SerializableMeters
{
get
{
return Meters.Cast<Meter>().ToArray();
}
set
{
Meters = new List<IMeter>(value.Cast<IMeter>());
}
}
And then later
var meters = xml.LoadFromXML<MeterWalkOrder>();
Debug.Assert(meters.Meters.Count == 2); // No assert.

C# Serialize a class with a List data member

I have this c# class:
public class Test
{
public Test() { }
public IList<int> list = new List<int>();
}
Then I have this code:
Test t = new Test();
t.list.Add(1);
t.list.Add(2);
IsolatedStorageFile storage = IsolatedStorageFile.GetUserStoreForApplication();
StringWriter sw = new StringWriter();
XmlSerializer xml = new XmlSerializer(t.GetType());
xml.Serialize(sw, t);
When I look at the output from sw, its this:
<?xml version="1.0" encoding="utf-16"?>
<Test xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" />
the values 1,2 I added to the list member variable dont show up.
So how can I fix this ? I made the list a property but it still doesnt seem to work.
I am using xml serialization here, are there any other serializers ?
I want performance! Is this the best approach ?
--------------- UPDATE BELOW -------------------------
So the actual class I want to serialize is this:
public class RoutingResult
{
public float lengthInMeters { get; set; }
public float durationInSeconds { get; set; }
public string Name { get; set; }
public double travelTime
{
get
{
TimeSpan timeSpan = TimeSpan.FromSeconds(durationInSeconds);
return timeSpan.TotalMinutes;
}
}
public float totalWalkingDistance
{
get
{
float totalWalkingLengthInMeters = 0;
foreach (RoutingLeg leg in Legs)
{
if (leg.type == RoutingLeg.TransportType.Walk)
{
totalWalkingLengthInMeters += leg.lengthInMeters;
}
}
return (float)(totalWalkingLengthInMeters / 1000);
}
}
public IList<RoutingLeg> Legs { get; set; } // this is a property! isnit it?
public IList<int> test{get;set;} // test ...
public RoutingResult()
{
Legs = new List<RoutingLeg>();
test = new List<int>(); //test
test.Add(1);
test.Add(2);
Name = new Random().Next().ToString(); // for test
}
}
But the XML produced by the serializer is this:
<RoutingResult>
<lengthInMeters>9800.118</lengthInMeters>
<durationInSeconds>1440</durationInSeconds>
<Name>630104750</Name>
</RoutingResult>
???
its ignoring both of those lists ?

1) Your list is a field, not a property, and the XmlSerializer will only work with properties, try this:
public class Test
{
public Test() { IntList = new List<int>() }
public IList<int> IntList { get; set; }
}
2) There are other Serialiation options, Binary the main other one, though there is one for JSON as well.
3) Binary is probably the most performant way, since it is typically a straight memory dump, and the output file will be the smallest.

list is not a Property. Change it to a publicly visible property, and it should be picked up.

I figured it out that XmlSerializer doesnt work if I use IList so I changed it to List, that made it work. As Nate also mentioned.