Does anyone know if there is an alternative to using attributes on C# properties to map to XML nodes when using XmlSerializer?
My issue is that I have an object called Article, with some properties (e.g. ID, Title, Body) and I do not want to add attributes directly to it (used elsewhere, etc, etc)...so I created a partial class and re-defined the properties and added the attributes there, but soon discovered that you cannot have duplicate properties in partial classes.
So I was wondering if anyone knew of any way that I could map the properties instead (in a similar fashion to n-hibernate, for example).
I'd appreciate any help.
There's a constructor of the XmlSerializer class that allows you to pass a XmlAttributeOverrides and thus alter the behavior at runtime.
Quote from the documentation:
The overrides parameter can be used to control how fields and
properties are encoded in XML. These settings override any attributes
that already exist on the objects. This can be useful when the source
code cannot be modified or multiple encodings are required for the
same classes.
You could implement IXmlSerializable directly. It requires some more code, but you will have full control without the need for attributes.
Related
I'm looking for a Serializer to persist my classes in text format (not binary). But...
I'm already using protobuf for binary serialization. It works pretty fine. As a side note, I would have prefer not to deal with field id (index) like with protobuf.
Before closing or voting to close this question, please consider these points:
The specificity of this question
If other question really apply to my requirements and are not too old
I'm looking for a serializer with the following properties:
Easy to use
Serialize in text (readable) either Json or XML would be fine
Free
Is documented
Support versioning easily (obsolete field, type change, property name change, ...)
Uses Attribute to define items to serialize (or not serialize)
Does not uses an index (ID like Protobuf)
Be able like Protobuf, to deserialize an object directly without any constructor. Be able to instanciate an object either if the object does not have any public constructor and does not have any constructor with no arguments.
Does not require me to change my class or member accessibility, ie:
Does not need default constructor
Can serialize fields
Can skip public property (when marked to do so)
Others points not essential:
The speed is not important
Open source is a nice bonus
Has some examples is a nice bonus
Some examples of what I prefer to not use:
Microsoft XMLSerializer and JsonSerializer does require default constructor.
I have hard time using Microsoft-DataContractSerializer, an easier solution would be welcome.
I have around 50 classes in polymorphic, inheritance relation. I used XmlSerializer to serialize them. Now for few classes I want to implement IXmlSerializable. So I started for one of class.This class not base class but derived directly from base class of all polymorphic relation.
After implementation, resultant XML contains tags only for above class which I have written in WriteXML method. There is no information for other classes. Very strange behavior!!!!
So please guide me to solve this issue, so that other classes information would maintain.
As I understand you correct - your xml contains properties that you implicit add in WriteXML (of current class)? But it is correct behavior. You should implicit add item as in example in description of interface.
If you need properties of base classes - add them. if you need properties of classes that inherit from this class - try to get them via reflection. Get Property Names using Reflection . But instead of typeof(MyClass) use .GetType() and check there how to get properties values.
Similar questions here and there.
End the ReadXml(XmlReader reader) method with the line
reader.Read();
seams to solves the problem...
I've got my fingers crossed that someone out there has a good understanding of the Microsoft XmlSerializer.
Basically, I have built a system for outputting XML on the back of the serializer which is now causing me a lot of hassle and I am trying to avoid a significant re-write.
Introduction
My current system employs a lot of derived classes.
For example,
BaseResponse -> CarParkResponse -> CarParkResponseInherited
BaseResponse and CarParkResponse (both in a library dll) are seperate from CarParkResponseInherited.
As a result, the base classes are ignorent of the derived class.
What I have done
-> Declared derived classes
I appreciate that in order for xmlserializer to do its thing, there are a number of ways to declare dervied classes.
Declare derived classes in base classes using XmlInclude
or
Declared types to be serialised and deserialised in xmlSerialiser. For example:
XmlSerializer serializer = new XmlSerializer(typeof(CarParkResponse), new Type[] { typeof(CarParkParameters), typeof(CarParkInformation) });
I have gone with the latter.
What I am trying to do
Because the derived classes are seperate and they share the same properties, what I am trying to do is serialize the dervied class as the subclass.
In other words deserialize CarParkResponseInherited as a CarParkResponse.
In "CarParkResponseInherited" I am using the declaration XmlTypeAttribute("CarParkResponse").
Initially this causes a problem when serialized
Types 'CarParkResponseInherited' and 'CarParkResponse' both use the XML type name, 'CarParkResponse', from namespace ''. Use XML attributes to specify a unique XML name and/or namespace for the type."
as the type is already in use "CarParkResponse" so I've declased XmlType("Response") in "CarParkResponse" to get around this.
The Problem
I am now trying to Deserialize the XML returned but I'm now getting the following problem.
The specified type was not recognized: name='CarParkResponse', namespace='', at OriginalRequest xmlns=''
Frustratingly the CarParkResponse is there. I am wondering if this is down to the fact I've used XmlType("Response") in the class and the serializer doesn't recognise the class as being type of CarParkResponse
So my question is
Basically is it possible to pass a derived class as a sub class and have it deserialized as the subclass using the XmlSerializer?
I have experimented with the xml produced.
For example, if I don't use the Serialization tags (such as XmlType() etc.) anywhere in my code. The xml produced will produce a carparkresponse element with "type" as an attribute.
The value is "CarParkResponseInherited". I have written some code that removes "Inherited" from the value which does allow it to be deserialized.
This approach is obviously not good so I am hoping there is a good way around this.
So...
if there is anyone out there that has had to patience to read through this post and can help or offer advice it would be most appreciated as I am all out of ideas.
Thanks.
It might be possible to do something using the XmlAttributeOverrides class. It's mostly used for specific property overrides, so it may or may not be the best thing for you.
The long way around would be to go ahead and serialize as the inherited class. Then, if the mappings are the same, deserialize the xml into the base class, and then, re-serialize into what you want.
Depending on how much or how little control you have over the assemblies, you could override the serialization on the inherited class so it does it as the base class.
I'm wondering how to exclude/strip certain properties of given type(s) (or collections of those) from being serialized using Json.NET library?
I tried to write my own contract resolver (inheriting from DefaultContractResolver) with no luck.
I know that I could be done using DataAnnotations, decorating the excluded properties with ScriptIgnoreAttribute, but it's not applicable in my scenario. The objects serialized can be virtually anything, so I don't know which properties to exclude at design-time. I know only the types of properties that should not be serialized.
It looks like a rather simple task, but unfortunately I couldn't find a decent solution anywhere...
BTW - I'm not bound to Json.NET library - if it can easily be done with default/other .NET JSON serializers it'd be an equally good solution for me.
UPDATE
The properties has to be excluded before trying to serialize them. Why?
Basically, the types of objects I'm receiving and serializing can have dynamic properties of type inheriting from IDynamicMetaObjectProvider. I'm not going to describe all the details, but the DynamicMetaObject returned from GetMetaObject method of these objects doesn't have DynamicMetaObject.GetDynamicMemberNames method implemented (throws NotImplementedException...). Summarizing - the problem is those objects (I need to exclude) doesn't allow to enumerate their properties, what Json.NET serializer tries to do behind the scenes. I always end up with NotImplementedException being thrown.
I have tried both the WCF JSON serialization as well as the System.Web.Script.Serialization.JavaScriptSerializer. I have found if you want solid control of the serialization process and do not want to be bound by attributes and hacks to make things work, the JavaScriptSerializer is the way to go. It is included in the .NET stack and allows you to create and register JavaScriptConverter subclasses to perform custom serialization of types.
The only restriction I have found that may cause you a problem is that you cannot easily register a converter to convert all subclasses of Object (aka, one converter to rule them all). You really need to have knowledge of common base classes or preregister the set of types up front by scanning an assembly. However, property serialization is entirely left up to you, so you can decide using simple reflection which properties to serialize and how.
Plus, the default serialization is much much much better for JSON than the WCF approach. By default, all types are serializable without attributes, enums serialize by name, string-key dictionaries serialize as JSON objects, lists serialize as arrays, etc. But for obvious reasons, such as circular trees, even the default behavior needs assistance from time to time.
In my case, I was supporting a client-API that did not exactly match the server class structure, and we wanted a much simpler JSON syntax that was easy on the eyes, and the JavaScriptSerializer did the trick every time. Just let me know if you need some code samples to get started.
Create your own contract resolver, override the method that creates the properties for an object and then filter the results to only include those that you want.
Have you considered using the ShouldSerialize prefix property to exclude the property of your specific type at runtime?
public class Employee
{
public string Name { get; set; }
public Employee Manager { get; set; }
public bool ShouldSerializeManager()
{
return (Manager != this);
}
}
My program creates xslt files and stores the information from custom classes there, this is done dynamically with attributes which mark the classes and properties I want to store in the xslt. This was quite easy because i just had to name the attribute like the property and fill the value with the object's toString() method.
Now I want to somehow reload that Information, create the same classes and fill the properties with those values. But how do i do that with e.g. Enums and other complex types if i don't know the type at compile time? Has to be some sort of parse method..
Any ideas?
If you just want to serialize your objects to XML and then desterilize them, and your objects contain interfaces, generic lists or other complex type you can use very useful serialization library http://www.codeproject.com/KB/XML/sharpserializer.aspx by Pawel Idzikowski.
It is really straight forward and can be very helpful in such cases.