My app serializes objects in streams. Here is a sample of what I need :
<links>
<link href="/users" rel="users" />
<link href="/features" rel="features" />
</links>
In this case, the object is a collection of 'links' object.
-----------First version
At first I used the DataContractSerializer, however you cannot serialize members as attributes (source)
Here is the object :
[DataContract(Name="link")]
public class LinkV1
{
[DataMember(Name="href")]
public string Url { get; set; }
[DataMember(Name="rel")]
public string Relationship { get; set; }
}
And here is the result :
<ArrayOflink xmlns:i="...." xmlns="...">
<link>
<href>/users</href>
<rel>users</rel>
</link>
<link>
<href>/features</href>
<rel>features</rel>
</link>
</ArrayOflink>
----------- Second version
Ok, not quiet what I want, so I tried the classic XmlSerializer, but... oh nooo, you cannot specify the name of the root element & of the collection's elements if the root element is a collection...
Here is the code :
[XmlRoot("link")]
public class LinkV2
{
[XmlAttribute("href")]
public string Url { get; set; }
[XmlAttribute("rel")]
public string Relationship { get; set; }
}
Here is the result :
<ArrayOfLinkV2>
<LinkV2 href="/users" rel="users" />
<LinkV2 href="/features" rel="features" />
<LinkV2 href="/features/user/{keyUser}" rel="featuresByUser" />
</ArrayOfLinkV2>
----------- Third version
using XmlSerializer + a root element :
[XmlRoot("trick")]
public class TotallyUselessClass
{
[XmlArray("links"), XmlArrayItem("link")]
public List<LinkV2> Links { get; set; }
}
And its result :
<trick>
<links>
<link href="/users" rel="users" />
<link href="/features" rel="features" />
<link href="/features/user/{keyUser}" rel="featuresByUser" />
</links>
</trick>
Nice, but I don't want that root node !! I want my collection to be the root node.
Here are the contraints :
- the serialization code is generic, it works with anything serializable
- the inverse operation (deserialization) have to work too
- I don't want to regex the result (I serialize directly in an output stream)
What are my solutions now :
- Coding my own XmlSerializer
- Trick XmlSerializer when it works with a collection (I tried, having it find a XmlRootElement and plurialize it to generate its own XmlRootAttribute, but that causes problem when deserializing + the items name still keeps the class name)
Any idea ?
What really bother me in that issue, is that what I want seems to be really really really simple...
Ok, here is my final solution (hope it helps someone), that can serialize a plain array, List<>, HashSet<>, ...
To achieve this, we'll need to tell the serializer what root node to use, and it's kind of tricky...
1) Use 'XmlType' on the serializable object
2) Code a 'smart-root-detector-for-collection' method, that will return a XmlRootAttribute
3) Push that XmlRootAttribute into the serializer
I told you it was tricky ;)
To improve this, you can :
A) Create a XmlTypeInCollectionAttribute to specify a custom root name (If the basic pluralization does not fit your need)
B) If possible, cache your XmlSerializer (in a static Dictionary for example).
In my testing, instanciating a XmlSerializer without the XmlRootAttributes takes 3ms. If you specify an XmlRootAttribute, it takes around 80ms (Just to have a custom root node name !)