Default Constructors and Proxy Classes

Question

Hi,

I have a question regarding default constructors and the way svcutil generates proxy. I‘m not sure if I’m thinking in the right way in exposing these classes as DTO’s. I greatly value your inputs,

 

With the same example given below

[DataContract]

    public class MyClass

    {

        private List<Child> _children;

           

        void MyClass

{

_children = new List<Child>();

}

[DataMember]

Public List<Child> Children

{

Get{return _children;}

set{_children = value;}

 

}

    }

 

I’m trying to expose this class via a service agent. And for that I’m using svcutil to generate the DTO Classes. How can I ensure that the client when it tries to do the following does not get a null value?

MyClass myInstance = new MyClass();

myInstance.Children.Add(new Child()); //Throws an exception as the Children is null

 

Am I doing the right thing in exposing these proxy class as DTO I greatly appreciate your response.

 

Thanks much,

Kumar

Answer 1

The constructor will be called if you create the object normally. However, it will not run if the object is deserialized off the wire.  If you need to have a default value in place during serialization/deserialization, you call use the Version Tolerant Attributes to do that.

Please see this for further information:

http://msdn2.microsoft.com/en-US/library/ms229752.aspx

Hope that helps.

Thanks!

Scott

Answer 2

I have the same requirement.

But from the reference link, I do not know in which way VTA will help.

Can anyone explain it more clearly?

 

Thanks a lot.

Answer 3

I read it again.

Maybe OnDeserializing Attribute can be used to solve it.

I will try it later.

Thanks again.