I'm trying to constrol where a class property is rendered when the class is serialized: I need the property to appear as an attribute on a specific element:
namespace ConsoleApplication6
{
public class Program
{
static void Main(string[] args)
{
var myClass = new MyClass();
myClass.MyList.Add(new Item() { ID = 1 });
myClass.MyList.Add(new Item() { ID = 2 });
myClass.Xxx = "Hello World!";
var sx = new XmlSerializer(myClass.GetType());
sx.Serialize(Console.Out, myClass);
}
public class MyClass
{
public MyClass()
{
MyList = new List<Item>();
}
public List<Item> MyList { get; set; }
[XmlAttributeAttribute(AttributeName = "x")]
public string Xxx { get; set; }
}
public class Item
{
public int ID { get; set; }
}
}
}
This serializes quite nicely into this:
<?xml version="1.0" encoding="ibm850"?>
<MyClass xmlns:xsi=" ... " xmlns:xsd=" ... " x="Hello World!">
<MyList>
<Item>
<ID>1</ID>
</Item>
<Item>
<ID>2</ID>
</Item>
</MyList>
</MyClass>
BUT: My problem is, I need the property Xxx to be rendered as an attribute on the <MyList> element rather than the <MyClass> root element, like this:
...
<MyList x="Hello World!">
...
I'm GUESSING this should be possible using XmlSerialization attributes on the class/properties, but I can't figure it out. I even tried creating a subclass of List adding the property Xxx to that, but the .NET XML serialization ignores the extra properties, and the XML output is just like the List<..> is normally serialized.
Update: Here's the code where I try to create a "custom list", that inherits from List<Item> and adds an extra property:
public class Program
{
static void Main(string[] args)
{
var myClass = new MyClass();
myClass.MyList.Add(new Item() { ID = 1 });
myClass.MyList.Add(new Item() { ID = 2 });
myClass.MyList.Xxx = "Hello World!";
var sx = new XmlSerializer(myClass.GetType());
sx.Serialize(Console.Out, myClass);
}
public class MyClass
{
public MyClass()
{
MyList = new CustomList();
}
public CustomList MyList { get; set; }
}
public class Item
{
public int ID { get; set; }
}
public class CustomList : List<Item>
{
[XmlAttributeAttribute(AttributeName = "x")]
public string Xxx { get; set; }
}
}
The output xml looks like this:
<?xml version="1.0" encoding="ibm850"?>
<MyClass xmlns:xsi=" ... " xmlns:xsd=" ... ">
<MyList>
<Item>
<ID>1</ID>
</Item>
<Item>
<ID>2</ID>
</Item>
</MyList>
</MyClass>
Notice how the Xxx property is not represented in the xml...
I think for that level of control you will need to look at using the IXmlSerializable interface. I don't think using attributes will work here.
According to this MSDN discussion:
XmlSerializer does not serialize any members if a collection. Only
collection items get serialized. This is by design, basically a
decision was made to handle collections as arrays not as classes with
multiple properties, so collections should look like arrays on the
wire, therefore they do not have any members other then collection
items, and can be “flattened” by adding the [XmlElement] to the member
of the ICollection type.
So apparently the flaw you describe is by design. Unless you decide to run the resulting XML through some transforms, I'm not sure how you plan to get this to work using the XML serialization attributes.
This post provides some additional information, including a few options:
When a class is inherited from List<>, XmlSerializer doesn't serialize other attributes
Summary:
IXmlSerializable (as mentioned by Kai)
DataContractSerializer
Create a new class where X (your attribute) is a property and provide an additional property that is a list (so instead of subclassing list, just create a wrapper class). For example:
public class MyListWrapper<T>
{
public MyListWrapper()
{
Data = new List<T>();
}
[XmlAttribute(AttributeName="x")]
public string Xxx { get; set; }
[XmlElement]
public List<T> Data { get; set; }
}
Note that this will output Items as "Data" elements. If you're willing to drop the generic type parameter on Data and make it List(Item) then you can get items.
Hope that helps!
Related
I'm truly sorry if the answer exist here under another name but I've been trying to figure this out for a week or so and haven't found anything similar.
So, I'm building an Item system for a game in unity. There is an Item class with these properties
public int ItemId;
public string ItemName;
For simplicity, let's say I want to have two derived classes, Weapon and Armor, with a BaseDamage property for Weapon and BaseArmor for Armor.
I also want to load the items in an ItemContainer class from XML and ideally, from the same XML file rather than one for the weapons, one for armors and one for, say, potions.
I've tried multiple ways but so far the only way I've been able to succeed is by adding the BaseDamage and BaseArmor to the Item base class... like this :
public class Item
{
[XmlAttribute("ID")] public int ItemID;
[XmlElement("Name")] public string ItemName;
[XmlElement("Damage")] public int ItemBaseDamage;
[XmlElement("Armor")] public int ItemBaseArmor;
}
and simply not adding the element to the XML file for some items :
<ItemCollection>
<Items>
<Item ID ="001">
<Name>Dagger</Name>
<Damage>10</Damage>
</Item>
<Item ID ="002">
<Name>Chain Mail</Name>
<Armor>5</Armor>
</Item>
</Items>
</ItemCollection>
It does work, but I feel like this isn't the correct way to do it. Another issue is that if I want to add a Scroll class with a certain function to cast the spell written on that scroll, I need to add the "SpellToCast" property to the base class AND add a CastSpell(Spell) function to it that could be called from any item, which is not what I want...
In short, I'd want to load multiple items from the XML but with each being of their intended derived class so that they get access to their respective functions and get their specific properties such as BaseDamage if it's a weapon.
I've tried to use an XmlElement called ItemClass of type class, but I get an error saying that XmlElement/XmlAttribute is not valid on this declaration type...
I also thought about using an abstract Item class instead but then how do I load the item ID to the abstract base class Item and then BaseDamage to the derived class, Weapon?
This is the code I use to (deserialize? I'm not sure that's the correct term) the XML file :
[XmlRoot("ItemCollection")]
public class ItemContainer
{
[XmlArray("Items")]
[XmlArrayItem("Item")]
public List<Item> items = new List<Item>();
public static ItemContainer Load(string itemPath)
{
TextAsset _xml = Resources.Load<TextAsset>(itemPath);
XmlSerializer serializer = new XmlSerializer(typeof(ItemContainer));
StringReader reader = new StringReader(_xml.text);
ItemContainer items = serializer.Deserialize(reader) as ItemContainer;
reader.Close();
return items;
}
}
So, any help is welcome,
Thanks
Try this code example, a good tool for xml and c# is xml2csharp
class Program
{
static void Main(string[] args)
{
var xml = File.ReadAllText("test.xml");
var serializer = new XmlSerializer(typeof(ItemCollection));
using (var reader = new StringReader(xml))
{
var items = serializer.Deserialize(reader) as ItemCollection;
}
}
}
[XmlRoot(ElementName = "Item")]
public class Item
{
[XmlElement(ElementName = "Name")]
public string Name { get; set; }
[XmlElement(ElementName = "Damage")]
public string Damage { get; set; }
[XmlAttribute(AttributeName = "ID")]
public string ID { get; set; }
[XmlElement(ElementName = "Armor")]
public string Armor { get; set; }
}
[XmlRoot(ElementName = "Items")]
public class Items
{
[XmlElement(ElementName = "Item")]
public List<Item> Item { get; set; }
}
[XmlRoot(ElementName = "ItemCollection")]
public class ItemCollection
{
[XmlElement(ElementName = "Items")]
public Items Items { get; set; }
}
While the first answer wasn't exactly what I was looking for, it did send me on the correct track as I looked into using multiple roots and by googling for that, I fell on a certain website and realized that the solution was simply to tell the XML file that I'm not going to use the Item Class but rather Weapon / Armor / Scroll and such so that they can be considered as their respective derived class.
Did it like this :
[XmlRoot("ItemCollection")]
public class ItemContainer
{
[XmlArray("Items")]
[XmlArrayItem("Weapon", Type = typeof(Weapon))]
[XmlArrayItem("Armor", Type = typeof(Armor))]
public List<Item> items = new List<Item>();
public static ItemContainer LoadItems(string itemPath)
{
TextAsset _xml = Resources.Load<TextAsset>(itemPath);
XmlSerializer serializer = new XmlSerializer(typeof(ItemContainer));
StringReader reader = new StringReader(_xml.text);
ItemContainer items = serializer.Deserialize(reader) as ItemContainer;
reader.Close();
return items;
}
}
I haven't looked at protoBuff, the only thing I found was protocol buffer, which seems to be what you were talking about. I'll keep it in mind but right now it might be a bit too much for my basic understanding of C# in general
<?xml version="1.0" encoding="utf-8" ?>
<ItemCollection>
<Items>
<Weapon Name ="Dagger">
<ID>01</ID>
<BaseDamage>10</BaseDamage>
</Weapon>
<Armor Name ="Chainmail">
<ID>04</ID>
<BaseArmor>5</BaseArmor>
</Armor>
</Items>
</ItemCollection>
I need to convert the XML string to List, the method should be generic. I wrote a method but its not performing as expected.
Scenario: #1
Model Class:
public class Employee {
public int EmpId { get; set; }
public string Name { get; set; }
}
XML:
<EmployeeList
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<Employee>
<EmpId>1</EmpId>
<Name>Emma</Name>
</Employee>
<Employee>
<EmpId>2</EmpId>
<Name>Watson</Name>
</Employee>
</EmployeeList>
Scenario: #2
Model Class:
public class Person {
public int PersonId { get; set; }
public string Name { get; set; }
}
XML:
<PersonList
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<Person>
<PersonId>1</EmpId>
<Name>Emma</Name>
</Person>
<Person>
<PersonId>2</EmpId>
<Name>Watson</Name>
</Person>
</PersonList>
I need a generic method to Convert the above said XML's to List<Employee> and List<Person>.
I used the following code
public static T[] ParseXML<T>(this string #this) where T : class {
var reader = XmlReader.Create(#this.Trim().ToStream(),new XmlReaderSettings() { ConformanceLevel = ConformanceLevel.Document });
return new XmlSerializer(typeof(T[])).Deserialize(reader) as T[];
}
But I'm getting NULL. Kindly assist me how to handle this.
I refereed lots of code but they are telling to specify the Root element as hard-coded value. But I need a generic method.
The Signature should be
public static T[] ParseXML<T>(this string #this) where T : class { }
Kindly assist me in this regards.
The default root name is ArrayOfThing, not ThingList, so you will need to tell the serializer:
var ser = new XmlSerializer(list.GetType(), new XmlRootAttribute("EmployeeList"));
However, you'll also need to cache and re-use this to prevent assembly memory leaks (only the most basic constructors automatically cache). A static read-only field on a generic type is a good bet, for example:
static class SerializerCache<T> {
public static readonly XmlSerializer Instance = new XmlSerializer(
typeof(List<T>), new XmlRootAttribute(typeof(T).Name + "List"));
}
then use SerializerCache<T>.Instance instead of new XmlSerializer
Obviously swap lists and arrays if you like...
I derived the answer from Marc Gravell - Convert XML string to List<T> without specifiying Element Root in C#, which I was marked as Correct.
public static class SerializerCache<T> {
public static readonly XmlSerializer Instance = new XmlSerializer(
typeof(List<T>), new XmlRootAttribute(typeof(T).Name + "List"));
}
public static class XMLHelper {
public static List<T> ParseXML<T>(this string #this) where T : class {
XmlSerializer serializer = SerializerCache<T>.Instance;
MemoryStream memStream = new MemoryStream(Encoding.UTF8.GetBytes(#this));
if(!string.IsNullorEmpty(#this) && (serializer != null) && (memStream != null)) {
return serializer.Deserialize(memStream) as List<T>;
}
else {
return null;
}
}
}
The Main Method is looks like
public static List<Employee> GetEmployeeList(string xml) {
return xml.ParseXML<Employee>();
}
I'm having issues deserializing XML which I can't quite figure out. Mainly, I'm trying to avoid having to nest classes when they're inside a list but not succeeding. For example:
[XmlRoot]
[Serializable]
public class Foo
{
[XmlElement("Bar")]
public BarElement Bar = new BarElement();
public class BarElement
{
[XmlElement("MoreBars")]
public List<MoreElement> MoreBars = new List<MoreElement>();
}
[XmlRoot("More")]
[Serializable]
public class MoreElement
{
[XmlAttribute("Attribute")]
public string Attribute { get; set; }
[XmlText]
public string Value { get; set; }
}
}
Corresponds to:
<Foo>
<Bar>
<MoreBars>
<More Attribute=""></More>
<More Attribute=""></More>
<More Attribute=""></More>
<More Attribute=""></More>
</MoreBars>
</Bar>
</Foo>
This almost works... but not quite. By adding XmlRoot to MoreElement, I'm trying to avoid the necessity of having to create a new class named "MoreBarsElement" that contains only a List of MoreElements, since it's already quite a chore to access "Foo.Bar.MoreBars.Value". Is this possible? If so, how would I do it?
Answering my own question - looks like I needed
[XmlArray("MoreBars"), XmlArrayItem(typeof(MoreElement), ElementName = "More")]
On the array item declaration. It works now, hurray!
I'd like to serialize a class to XML, assigning an XML attribute to it. Snippet:
[XmlType(TypeName = "classmy")]
public class MyClass2 : List<object>
{
[XmlAttribute(AttributeName = "myattr")]
public string Name { get; set; }
}
public class MyConst
{
public MyConst()
{
MyClass2 myClass2 = new MyClass2 { 10, "abc" };
myClass2.Name = "nomm";
XmlSerializer serializer = new XmlSerializer(typeof(MyClass2));
serializer.Serialize(Console.Out, myClass2);
}
}
But the resulting XML looks like this
<?xml version="1.0" encoding="IBM437"?>
<classmy xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<anyType xsi:type="xsd:int">10</anyType>
<anyType xsi:type="xsd:string">abc</anyType>
</classmy>
All well and good, with the only exception being that myClass2.Name is not serialized. I was expecting something in the line of
<classmy myattr="nomm" [...]>[...]</classmy>
... Why isn't that serialized, and how can it be?
dont derive List<T>, create class with member List
[XmlType(TypeName = "classmy")]
public class MyClass2
{
[XmlAttribute(AttributeName = "Items")]
List<object> Items { get; set; } //need to change type in `<>`
[XmlAttribute(AttributeName = "myattr")]
public string Name { get; set; }
}
Alternative solution: use an array instead of a list and XmlElement
[XmlType(TypeName = "classmy")]
public class MyClass2
{
[XmlElement(ElementName = "Items")]
public object[] Items { get; set; }
[XmlAttribute(AttributeName = "myattr")]
public string Name { get; set; }
}
XmlSerializer treats List<> in special way:
XmlSerializer can process classes that implement IEnumerable or ICollection differently if they meet certain requirements. A class that implements IEnumerable must implement a public Add method that takes a single parameter. The Add method's parameter must be consistent (polymorphic) with the type returned from the IEnumerator.Current property returned from the GetEnumerator method. A class that implements ICollection in addition to IEnumerable (such as CollectionBase) must have a public Item indexed property (an indexer in C#) that takes an integer, and it must have a public Count property of type integer. The parameter passed to the Add method must be the same type as that returned from the Item property, or one of that type's bases. For classes implementing ICollection, values to be serialized will be retrieved from the indexed Item property rather than by calling GetEnumerator. Also note that public fields and properties will not be serialized, with the exception of public fields that return another collection class (one that implements ICollection). MSDN - scroll to XML Serialization Considerations
That why it serialized Your class as a list of objects only, without Your property. The best solution is to include List as class public property and mark it as XmlElement.
is it possible to use C# XmlSerialization API to store single class in two different ways ?
For example
class Test
{
int group1_attr1;
int group1_attr2;
int group2_attr1;
}
I would like to have a way how to split class fields into two parts(groups - with specified attributes) and each time I call Serialize to control which part will be stored. For example if saving as group1
<?xml version="1.0" encoding="utf-8"?>
<Test xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org /2001/XMLSchema">
<group1_attr1>0</group1_attr1>
<group1_attr2>0</group1_attr2>
</Test>
if saving as group2
<?xml version="1.0" encoding="utf-8"?>
<Test xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org /2001/XMLSchema">
<group2_attr1>0</group2_attr1>
</Test>
Is there a way how to do it in a "clean" way ? If not in xmlserialization then in binary perhaps ?
Then I would like to know what is the best way how to merge those two files into single instance of Test. (Note that fields from group1 and group2 do not overlap)
Here's code demonstrating how to serialize like you want, however, deserialization will be more tricky because it's not straightforward to deserialize into an existing instance (see How to use XmlSerializer to deserialize into an existing instance?).
public class Test
{
public int group1_attr1;
public int group1_attr2;
public int group2_attr1;
}
class Program
{
static void Main(string[] args)
{
System.Xml.Serialization.XmlAttributes xa =
new System.Xml.Serialization.XmlAttributes();
xa.XmlIgnore = true;
System.Xml.Serialization.XmlAttributeOverrides xo1 =
new System.Xml.Serialization.XmlAttributeOverrides();
xo1.Add(typeof(Test), "group1_attr1", xa);
xo1.Add(typeof(Test), "group1_attr2", xa);
System.Xml.Serialization.XmlAttributeOverrides xo2 =
new System.Xml.Serialization.XmlAttributeOverrides();
xo2.Add(typeof(Test), "group2_attr1", xa);
System.Xml.Serialization.XmlSerializer xs1 =
new System.Xml.Serialization.XmlSerializer(typeof(Test), xo1);
System.Xml.Serialization.XmlSerializer xs2 =
new System.Xml.Serialization.XmlSerializer(typeof(Test), xo2);
Test t1 = new Test();
t1.group1_attr1 = 1;
t1.group1_attr2 = 2;
t1.group2_attr1 = 3;
using (System.IO.StringWriter sw = new System.IO.StringWriter())
{
xs1.Serialize(sw, t1);
Console.WriteLine(sw);
}
using (System.IO.StringWriter sw = new System.IO.StringWriter())
{
xs2.Serialize(sw, t1);
Console.WriteLine(sw);
}
}
}
The deserialization could maybe merge the XML before deserializing:
Test t2 = new Test();
System.Xml.Serialization.XmlSerializer xs3 = new System.Xml.Serialization.XmlSerializer(typeof(Test));
string mergedXml = MergeSerializedXml(group1, group2);
using (System.IO.StringReader sr = new System.IO.StringReader(mergedXml))
{
t2 = (Test)xs3.Deserialize(sr);
}
...
static string MergeSerializedXml(string x1, string x2)
{
System.Xml.XmlDocument xd = new System.Xml.XmlDocument();
xd.LoadXml(x1);
System.Xml.XmlReaderSettings xrs = new System.Xml.XmlReaderSettings();
xrs.IgnoreWhitespace = true;
using (System.Xml.XmlReader xr = System.Xml.XmlReader.Create(new System.IO.StringReader(x2), xrs))
{
while (xr.Read() && !xr.IsStartElement())
;
xr.MoveToContent();
xr.Read();
System.Xml.XmlNode xn = xd.ChildNodes[1];
do
{
xn.AppendChild(xd.ReadNode(xr));
} while (xr.NodeType != System.Xml.XmlNodeType.EndElement);
}
return xd.OuterXml;
}
Composition will sort of allow you to do this, http://en.wikipedia.org/wiki/Composition_over_inheritance. If you serialize CompositeGroup1 then stick it in an instance of CompositeData. Do the same for CompositeGroup2. There's no way to do what you are asking for, as you asked it, with the built in serializers. When you serialize data it will always generate the full serialization for that type.
class CompositeData
{
public CompositeGroup1 Group1 { get; set; }
public CompositeGroup2 Group2 { get; set; }
}
class CompositeGroup1
{
public int Attr1 { get; set; }
public int Attr2 { get; set; }
}
class CompositeGroup2
{
public int Attr1 { get; set; }
}
You could also consider making CompositeData implement abstract classes, one for each grouping. You can use some other JSON serializers that use the type passed in instead of the runtime type to generate the serialized data.
var json1 = serializer.Serialize<AbstractGroup1>(new CompositeData());
var json2 = serializer.Serialize<AbstractGroup2>(new CompositeData());
However, putting them back together again would still be your problem.
You can loook into my project, Xml Serialization Framework, that will use interfaces idiom to solve the same issue as you might have
Example:
To serialize class instance/object
class Person
{
public string Name { get; set; }
}
you would probably declare interfaces to use in metadata driven xml runtime serialization:
interface IPersonRoot
{
string Name { get; set; }
}
[XmlRootSerializer("Body")]
interface IPersonCustomRoot
{
string Name { get; set; }
}
interface IPersonCustomAttribute
{
[XmlAttributeRuntimeSerializer("Id")]
string Name { get; set; }
}
This framework supports even working with partial update of living instances using particular interfaces/XML formats:
to/from XML using IPersonRoot interface:
<Person>
<Name>John Doe</Name>
</Person>
to/from XML using IPersonCustomRoot interface:
<Body>
<Name>John Doe</Name>
</Body>
to/from XML using IPersonCustomAttribute interface:
<Person Id="John Doe" />
Have a nice day,
Cheers ;)
Artur M.