Question

I’ve got a base class for all my custom entity collections, a simple version of it is this:

[Serializable]
public class CollectionBase<T> : List<T> where T : IEntity
{

    public bool IsDirty {get;}

    public new void Add(T item)
    {
        this.SetDirty();
        base.Add(item);
        item.MadeDirty += new EventHandler(item_MadeDirty);
    }

    // Other standard list methods overridden here
    ...

    public void SetDirty() { } // Mark the collection as dirty

    private void item_MadeDirty(object sender, EventArgs e)
    {
        this.SetDirty();
    }

}

The collections sit within a serialized class that sits in Session (i.e. Customer class in session has a collection of Order entities). The problem is that my entity base class’s MadeDirty event is as follows:

[field: NonSerialized()]
public event EventHandler MadeDirty;

Unfortunately, I cannot just remove the NonSerialized attribute on the event, because this causes issues in the session state server when deployed to my application server.

Is there any way that I can capture a deserialized completion event on the CollectionBase so I can iterate through all the items and re-assign the MadeDirty event on each deserialization from the Session? I.e.

private void OnDeserialized(object sender, EventArgs e)
{
   foreach (T item in this)
   {
      item.MadeDirty+= new EventHandler(item_MadeDirty);
   }
}

But, I can’t imagine this is the first time anyone’s come across this issue, so is there a better alternative?

Answer 1

Yes, you can add a method with a special attribute and the right signature to your class:

[OnDeserializedAttribute()]
private void RunThisMethod(StreamingContext context)
{ 
    // post-serialize your class
}