Question

I have the following entity base class marked as serializable:

[Serializable]
public abstract class EntityBase
{
    public bool Is_ActiveNull = true;
    [XmlElement(ElementName = "Is_ActiveFromNull")]
    ...  

I have then concrete entity which inherits from base entity:

[Serializable]
public class ContactEntity : EntityBase
{
 ...

I have a WCF service which uses this entity as a input parameter in contract.

When I create a service reference from the client it creates a reference.cs which ignores default values for field Is_ActiveNull.

This is EntityBase class in reference.cs file:

public partial class EntityBase : object, System.Runtime.Serialization.IExtensibleDataObject, System.ComponentModel.INotifyPropertyChanged 
{
    private bool Is_ActiveNullField;

    [System.Runtime.Serialization.DataMemberAttribute(IsRequired=true)]
    public bool Is_ActiveNull {
        get {
            return this.Is_ActiveNullField;
        }
        set {
            if ((this.Is_ActiveNullField.Equals(value) != true)) {
                this.Is_ActiveNullField = value;
                this.RaisePropertyChanged("Is_ActiveNull");
            }
        }
    }
    ...

In this case Is_ActiveNullField is set to false by default.

My question is how can I preserve the default value?

thanks

Answer 1

Their is no such attribute that will preserve the default value for public bool Is_ActiveNull

But you can achieve it when Deseralizing happens like this

You will have to add EmitDefaultValue on you field

 [System.Runtime.Serialization.DataMemberAttribute(IsRequired=true, EmitDefaultValue=false)]
    public bool Is_ActiveNull {

and then 

[OnDeserializing]
    void BeforeDeserialization(StreamingContext ctx)
    {
        this.Is_ActiveNull = false;
    }

Mind you the MSDN also gives a Not on practice for EmitDefaultValue

Setting the EmitDefaultValue property to false is not a recommended
practice. It should only be done if there is a specific need to do so
(such as for interoperability or to reduce data size).