I'm trying to figure out how to serialize the following class into XML (in a specific way, see below):
[XmlRoot("Farm")]
public class Farm
{
[XmlArray]
[XmlArrayItem("Person", typeof(Person))]
[XmlArrayItem("Dog", typeof(Dog))]
public List<Animal> Animals { get; set; }
}
(Assume that Dog and Person both derive from Animal, and they both have a Name property which is decorated with [XmlAttribute("Name")].)
I need to be able to create this object:
var myFarm = new Farm
{
Animals = new List<Animal> {
new Person { Name = "Bob" },
new Dog { Name = "Fido" }
}
};
...and have it serialize to the following document:
<?xml version="1.0"?>
<Farm>
<Person Name="Bob"/>
<Dog Name="Fido"/>
</Farm>
But, when I serialize myFarm (result outputs to console) like this:
var serializer = new XmlSerializer(typeof(Farm));
var namespaces = new XmlSerializerNamespaces();
namespaces.Add("", "");
serializer.Serialize(System.Console.Out, myFarm, namespaces);
...the result is this:
<?xml version="1.0"?>
<Farm>
<Animals>
<Person Name="Bob"/>
<Dog Name="Fido"/>
</Animals>
</Farm>
Notice the extra unwanted Animals element. How do I get rid of this? Changing the XML schema is not an option, but changing the code is. I'd really just like to be able to get around this problem and am hoping someone knows of an easy fix (or knows for a fact that there is not an easy fix).
Thanks!
Use the following attributes instead:
[XmlRoot("Farm")]
public class Farm
{
[XmlElement("Person", typeof(Person))]
[XmlElement("Dog", typeof(Dog))]
public List<Animal> Items { get; set; }
}
Related
I am trying to use the XmlSerializer class in C# to deserialize some XML that I am pulling from someone. Unfortunately, they have their root element named "Employee", and then the inner elements inside that root element are also named "Employee":
<Employee xmlns="http://www.testxmlns.com/employee">
<Employee>
<OtherElement>OE</OtherElement>
...
</Employee>
<Employee>
<OtherElement>OE</OtherElement>
...
</Employee>
</Employee>
I was able to find another question that is very similar, but not exactly. Here is what my current object looks like:
[XmlType("Employee")]
[XmlRootAttribute(Namespace = "http://www.testxmlns.com/employee", IsNullable = true)]
public class Employee
{
[XmlElement("Employee")]
public Employee[] InnerEmployee;
[XmlElement("OtherElement")]
public String OtherElement;
...
}
When I run the following, everything seems to work (no exceptions thrown), but everything in the returned object is null, including the inner list of Employee objects, which should not be null based on the XML I am inputting:
Employee retObj;
XmlSerializer serializer = new XmlSerializer(typeof(Employee));
using (TextReader sr = new StringReader(xmlString))
{
retObj = (Employee)serializer.Deserialize(sr);
}
return retObj;
Any help would be appreciated!
You can see in this fiddle that if I take your code and run it... it works!
What I would suggest, however, is to have two classes: one for the 'root' and one for each child element. This would make it less confusing to work with:
[XmlRoot("Employee", Namespace = "http://www.testxmlns.com/employee")]
public class EmployeeRoot
{
[XmlElement("Employee")]
public Employee[] Employees { get; set; }
}
public class Employee
{
public string OtherElement { get; set; }
}
You can see in this fiddle that this also works.
I need to read this xml file:
<?xml version="1.0" encoding="UTF-8"?>
<Products>
<Product Name="Prod1">
<Description>Desc1</Description >
<Price>100</Price >
<Stock>200</Stock>
</Product>
<Product Name="Prod2">
<Description>Desc2</Description >
<Price>50</Price >
<Stock>400</Stock>
</Product>
</Products>
my idea was do something like this:
public ICollection<ProductDTO> importtProducts()
{
XmlSerializer deserializer = new XmlSerializer(typeof(List<ProductDTO>));
TextReader textReader = new StreamReader(#"c:\importers\xmlimporter.xml");
List<ProductDTO> prods;
prods = (List<ProductDTO>)deserializer.Deserialize(textReader);
textReader.Close();
XDocument doc = XDocument.Load(#"c:\importers\xmlimporter.xml");
foreach (var prod in doc.Root.Descendants("Product").Distinct())
{
//work with the prod in here
}
return some prods..;
}
but I'm having some problems with the root item, the xmlSerializer type.
does someone know which type should I use?
List, IList, ICollection, IEnumerable....
thanks a lot!
Consider creating one Products object with a List. You can then mark your objects as such:
public class Products
{
[XmlElement("Product", Type = typeof(Product))]
public List<Product> Products { get; set; }
}
public class Product
{
[XmlAttribute("Name")]
public string Name { get; set; }
[XmlElement("Description")]
public string Description { get; set; }
...
}
This will generate to a Products class that has a list of type Product when using:
XmlSerializer deserializer = new XmlSerializer(typeof(Products));
without specifying the type as a list
UPDATE
I added XmlAttribute("Name") to demonstrate the solution to the additional issue. #pratik-gaikwad relayed the solution before I did.
I have an XML file with the following format:
<?xml version="1.0" encoding="UTF-8"?>
<Items>
<Item Property1="A" Property2="B" />
<Item Property1="C" Property2="D" />
</Items>
I need to read the <Item> elements as objects of class MyClass using an XmlSerializer.
public class MyCLass
{
[XmlAttribute]
public string Property1 { get; set; }
[XmlAttribute]
public string Property2 { get; set; }
}
Currently, I have the following code to read the file:
XmlSerializer serializer =
new XmlSerializer(typeof(MyClass[]), new XmlRootAttribute(#"Items"));
MyClass[] list = (MyClass[])serializer.Deserialize(...);
Since the element name <Item> is different from the class name MyCLass, the elements in the array are not deserialized at all. The above code works if I rename MyClass to Item, but unfortunately I am not allowed to change the XML file or the class names.
How do I go about mapping the two so that the file can be read correctly?
Thanks in advance!
Use a wrapper class that contains the array, this will allow you to apply the XmlElement attribute:
public class MyClassList
{
[XmlElement("Item")]
public MyClass[] Items { get; set; }
}
var items = new[]
{
new MyClass { Property1 = "A", Property2 = "B" },
new MyClass { Property1 = "C", Property2 = "D" },
};
var list = new MyClassList { Items = items };
using (var writer = new StringWriter())
{
var xs = new XmlSerializer(typeof(MyClassList), new XmlRootAttribute("Items"));
xs.Serialize(writer, list);
writer.ToString().Dump();
}
Personally I would serialize and deserialize manually - I've found that it's easier to get whatever flexibility you want that way rather than spending a long time messing around with the built-in serialization and living with the various restrictions it imposes. LINQ to XML makes it pretty simple. For example, in this case:
XDocument doc = XDocument.Load("test.xml");
// You could use an array if you really wanted, of course.
List<MyClass> list = doc.Root
.Elements("Item")
.Select(x => new MyClass {
Property1 = (string) x.Attribute("Property1"),
Property2 = (string) x.Attribute("Property2"),
})
.ToList();
Admittedly this will get hairy if you need to serialize objects with complicated relationships (two objects referring to the same child or whatever) but I've had a great deal of success with it in the past.
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>();
We've already established previously that DCS serializes/deserializes objects alphabetically. However, after further investigation I've discoverred this is not entirely true.
If we have a structure like this:
[DataContract]
public class Content
{
[DataMember]
public string Title;
[DataMember]
public string Slug;
[DataMember]
public string Description;
}
[DataContract]
public class TextContent : Content
{
[DataMember]
public string Text;
}
and have an object of type TextContent to serialize, DCS will do this:
<Content i:type="TextContent" ...>
<Description>desc</Description>
<Slug>some-slug</Slug>
<Title>content title</Title>
<Text>some content</Text>
</Content>
So as you can see, the property from the inheriting class is attached to the end of the serialized XML fragment even though it should be before Title. DCS doesn't go over the combined properties and reorder them.
I've noticed this when I was manually adding Text element in front of Title element and deserialization just didn't want to work. That's why I performed a serialization of a new object and figured this out.
My questions are:
This can't be common knowledge?? Anyone else noticed this?
Anyone knows of a better serializer (all I ever find if I search for it is the old XmlSerializer and DCS) because this issue with DCS's ordering is extremely annoying? I know we can use the Order attribute but that only enables us to align with one external XML source. What if we have three, four or more third party XML providers which all generate perfectly valid XML but our app is nitpicking about elements order (because of DCS)?
The base types are always first in the order. You can define the order of the serialized properties of a object with respect of the Order property of the DataMember attribute (see http://msdn.microsoft.com/en-us/library/ms729813.aspx)
There's the NetDataContractSerializer but the only difference between it and the DCS is that it enables type sharing between the client and the server but you lose the forward compatibility because both sides have to serialize/deserialize into the same type..
There's also the C# wrapper for protocol buffer on codeplex:
http://code.google.com/p/protobuf-net/
I haven't tried it out myself, but it's supposed to be much faster and lightweight. As to your actual questions:
doubt it, I certainly never
noticed this :-P
can you give an example where the ordering of elements actually mattered? I haven't come across this myself (I guess that's why most of us haven't noticed this behavior..), but with the proto-buf serializer this will undoubtly be a problem..
If you need to be able to serialize to match an external schema, then you obviously shouldn't be using the DataContractSerializer. That's not what it's for.
You can either use the XmlSerializer, which is intended to give you more control over the serialized XML, or implement IXmlSerializable, and gain complete control over the XML, or you can write your own custom serialization using LINQ to XML. This will let you do exactly what you mention - serialize the same data in different ways. Example:
Data
internal class Person
{
internal string Name { get; set; }
internal string Telephone { get; set; }
internal Address HomeAddress { get; set; }
internal Address WorkAddress { get; set; }
}
internal class Address
{
internal string Line1 { get; set; }
internal string Line2 { get; set; }
internal string City { get; set; }
internal string State { get; set; }
internal string PostalCode { get; set; }
}
Test Program
private static void Main()
{
var person = new Person
{
Name = "John Saunders",
Telephone = "something",
HomeAddress = new Address
{
Line1 = "Line 1",
Line2 = "Line 2",
City = "SomeCity",
State = "SS",
PostalCode = "99999-9999",
},
WorkAddress = new Address
{
Line1 = "Line 1a",
Line2 = "Line 2a",
City = "SomeCitay",
State = "Sa",
PostalCode = "99999-999a",
},
};
XDocument personWithElements = SerializeAsElements(person);
personWithElements.Save("PersonWithElements.xml");
XDocument personWithAttributes = SerializeAsAttributes(person);
personWithAttributes.Save("PersonWithAttributes.xml");
}
Serialization as Elements:
private static XDocument SerializeAsElements(Person person)
{
return new XDocument(
new XElement("Person",
new XElement("Name", person.Name),
new XElement("Telephone", person.Telephone),
SerializeAddressAsElements(person.HomeAddress, "HomeAddress"),
SerializeAddressAsElements(person.WorkAddress, "WorkAddress"))
);
}
private static XElement SerializeAddressAsElements(Address address, string elementName)
{
return new XElement(elementName,
new XElement("Line1", address.Line1),
new XElement("Line2", address.Line2),
new XElement("City", address.City),
new XElement("State", address.State),
new XElement("PostalCode", address.PostalCode)
);
}
Serialization as Attributes:
private static XDocument SerializeAsAttributes(Person person)
{
return new XDocument(
new XElement("Person",
new XAttribute("Name", person.Name),
new XAttribute("Telephone", person.Telephone),
SerializeAddressAsAttributes(person.HomeAddress, "HomeAddress"),
SerializeAddressAsAttributes(person.WorkAddress, "WorkAddress"))
);
}
private static XElement SerializeAddressAsAttributes(Address address, string elementName)
{
return new XElement(elementName,
new XAttribute("Line1", address.Line1),
new XAttribute("Line2", address.Line2),
new XAttribute("City", address.City),
new XAttribute("State", address.State),
new XAttribute("PostalCode", address.PostalCode)
);
}
PersonWithElements:
<?xml version="1.0" encoding="utf-8"?>
<Person>
<Name>John Saunders</Name>
<Telephone>somethine</Telephone>
<HomeAddress>
<Line1>Line 1</Line1>
<Line2>Line 2</Line2>
<City>SomeCity</City>
<State>SS</State>
<PostalCode>99999-9999</PostalCode>
</HomeAddress>
<WorkAddress>
<Line1>Line 1a</Line1>
<Line2>Line 2a</Line2>
<City>SomeCitay</City>
<State>Sa</State>
<PostalCode>99999-999a</PostalCode>
</WorkAddress>
</Person>
PersonWithAttributes:
<?xml version="1.0" encoding="utf-8"?>
<Person Name="John Saunders" Telephone="somethine">
<HomeAddress Line1="Line 1" Line2="Line 2" City="SomeCity" State="SS" PostalCode="99999-9999" />
<WorkAddress Line1="Line 1a" Line2="Line 2a" City="SomeCitay" State="Sa" PostalCode="99999-999a" />
</Person>