.NET, C#: How to add a custom serialization attribute that acts as ISerializable interface

Question

I am doing some serialization of db linq objects, which contain EntitySet and EntityRef classes.

I found a pretty easy way to deal with serialization of these classes, by simply using ISerializable to properly handle members of this type (converting them to lists for serialization, and undoing it on deserialization).

However, it would be really nice if I could do:

[Serializable]
[SerializeLinqEntities]
partial class Person
{ ... }

Instead of:

partial class Person : ISerializable
{
  public virtual void GetObjectData( SerializationInfo si, StreamingContext ctxt )
  {
    EntitySerializer.Serialize(this, typeof(Person), si, ctxt);
  }

  protected Person( SerializationInfo si, StreamingContext ctxt )
  {
    EntitySerializer.Deerialize(this, typeof(Person), si, ctxt);
  }
}

Is there a way to do this? I looked through the serialization classes and couldn't seem to find any way to setup custom serialization filter routines (where I could look for my custom attribute).

Thanks!

Looks like IClientFormatterSinkProvider and IServerFormatterSinkProvider will allow me to provide a BinaryFormatter with my custom SurrogateSelector set. Thanks again Sergey! — marq
– marq, Commented Feb 1, 2010 at 18:28
Hmm... so, as it turns out, Microsoft has made this a lot more difficult than it looks. See the following link: 123aspx.com/Rotor/RotorSrc.aspx?rot=40027 Sink providers, as it turns out, are quite complex, and it's not as simple as just implementing one. I really wish they'd provided better interface API's to interface with binary serialization... — marq
– marq, Commented Feb 3, 2010 at 5:45

Zé Carlos · Accepted Answer · 2018-11-14 16:39:11Z

8

Yes, you can do this by implementing ISerializationSurrogate and ISurrogateSelector interfaces.

Something like this:

[AttributeUsage(AttributeTargets.Class)]
public class SerializeLinqEntities : Attribute
{
}

public class LinqEntitiesSurrogate : ISerializationSurrogate
{
    public void GetObjectData(
      object obj, SerializationInfo info, StreamingContext context)
    {
        EntitySerializer.Serialize(this, obj.GetType(), info, context);
    }

    public object SetObjectData(
      object obj, SerializationInfo info,
      StreamingContext context, ISurrogateSelector selector)
    {
        EntitySerializer.Deserialize(obj, obj.GetType(), info, context);
        return obj;
    }
}


/// <summary>
/// Returns LinqEntitySurrogate for all types marked SerializeLinqEntities
/// </summary>
public class NonSerializableSurrogateSelector : ISurrogateSelector
{
    public void ChainSelector(ISurrogateSelector selector)
    {
        throw new NotImplementedException();
    }

    public ISurrogateSelector GetNextSelector()
    {
        throw new NotImplementedException();
    }

    public ISerializationSurrogate GetSurrogate(
      Type type, StreamingContext context, out ISurrogateSelector selector)
    {
        if (!type.IsDefined(typeof(SerializeLinqEntities), false))
        {
            //type not marked SerializeLinqEntities
            selector = null;
            return null;
        }
        selector = this;
        return new LinqEntitiesSurrogate();
    }

}

[SerializeLinqEntities]
public class TestSurrogate
{
    public int Id { get; set; }
    public string Name { get; set; }
}

class Program
{
    static void Main(string[] str)
    {

        var ns1 = new TestSurrogate {Id = 47, Name = "TestName"};
        var formatter = new BinaryFormatter();
        formatter.SurrogateSelector = new NonSerializableSurrogateSelector();

        using (var ms = new MemoryStream())
        {
            formatter.Serialize(ms, ns1);
            ms.Position = 0;

            var ns2 = (TestSurrogate) formatter.Deserialize(ms);
            // Check serialization
            Debug.Assert(ns1.Id == ns2.Id);
            Debug.Assert(ns1.Name == ns2.Name);
        }
    }
}

edited Nov 14, 2018 at 16:39

Zé Carlos

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answered Feb 1, 2010 at 8:16

Sergey Teplyakov

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3 Comments

marq Over a year ago

That is exactly what I want (ISurrogateSelector is exactly what I was looking for). So, final question - is there a way to use this with automated serialization? My serializing is happening via an RPC call (using a MarshalByRefObject).

Rory Over a year ago

+1 I didn't even think of ISerializationSurrogate because the question explicitly mentioned attributes. The only problem with this solution comes when you don't have access to the formatter instance to set the SurrogateSelector property.

Sergey Teplyakov Over a year ago

In WCF you can easily use surrogates (msdn.microsoft.com/en-us/library/ms733064.aspx). I don't used surrogates with .net remoting. Maybe Custom Sinks can helps you (codeproject.com/KB/IP/customsinks.aspx).

Rory · Accepted Answer · 2010-02-01 04:52:25Z

0

Unfortunately no, ISerializable is an interface designed to allow you to control the serialization process while the SerializableAttribute is just a marker that says "this class can be serialized". However, you could look into something like PostSharp to add this functionality (take a look at the CompositionAspect).

answered Feb 1, 2010 at 4:52

Rory

2,7421 gold badge20 silver badges11 bronze badges

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