I just realized something crazy, which I assumed to be completely impossible : when deserializing an object, the DataContractSerializer doesn't call the constructor !
Take this class, for instance :
[DataContract]
public class Book
{
public Book()
{ // breakpoint here
}
[DataMember(Order = 0)]
public string Title { get; set; }
[DataMember(Order = 1)]
public string Author { get; set; }
[DataMember(Order = 2)]
public string Summary { get; set; }
}
When I deserialize an object of that class, the breakpoint is not hit. I have absolutely no idea how it is possible, since it is the only constructor for this object !
I assumed that perhaps an additional constructor was generated by the compiler because of the DataContract
attribute, but I couldn't find it through reflection...
So, what I'd like to know is this : how could an instance of my class be created without the constructor being called ??
NOTE: I know that I can use the OnDeserializing
attribute to initialize my object when deserialization begins, this is not the subject of my question.
DataContractSerializer
(like BinaryFormatter
) doesn't use any constructor. It creates the object as empty memory.
For example:
Type type = typeof(Customer);
object obj = System.Runtime.Serialization.
FormatterServices.GetUninitializedObject(type);
The assumption is that the deserialization process (or callbacks if necessary) will fully initialize it.