Question

I’ve got some serialisation code set up as follows:

    static void SerialiseObject(Object o, String path)
    {
        IFormatter formatter = new BinaryFormatter();
        Stream stream = new FileStream(path, FileMode.Create);
        formatter.Serialize(stream, o);
        stream.Close();
    }
    static Object DeserialiseObject(String path)
    {
        IFormatter formatter = new BinaryFormatter();
        Stream stream = new FileStream(path, FileMode.Open, FileAccess.Read);
        Object o = (Object)formatter.Deserialize(stream);
        stream.Close();
        return o;
    }

And a class with the following member defined:

[Serializable]
public class CircuitModel
{
    public Dictionary<String, Bus> Buses { protected set; get; }
    ...
}

I populate the Dictionary, and then the following code successfully serialises and deserialises the dictionary, with all Bus objects intact:

SerialiseObject(CircuitModel.Buses, "temp.bin");
Object o = DeserialiseObject("temp.bin");

But when I try to do the same for CircuitModel:

SerialiseObject(CircuitModel, "temp.bin");
Object o = DeserialiseObject("temp.bin");

CircuitModel.Buses has been initialised, but is empty.

I’ve also tried implementing serialisation with ISerializable (for the Bus and CircuitModel classes) and had exactly the same problem

Any idea as to why this would be happening?

Answer 1

I think you have something more sinister going on with your child collection because binary serialization of Dictionaries within classes does work just fine.

    [TestFixture]
public class SerializeTest
{

    [Test]
    public void TestSer()
    {
        var parent = new Parent
                        {
                            Name = "Test"
                        };
        parent.Children.Add("Child1", new Child {Name = "Child1"});
        parent.Children.Add( "Child2", new Child { Name = "Child2" } );

        SerialiseObject(parent, "test.bin");
        var copy = DeserialiseObject("test.bin") as Parent;

        Assert.IsNotNull(copy);
        Assert.AreEqual(2, copy.Children.Count);
        Assert.IsTrue(copy.Children.ContainsKey("Child1"));
        Assert.AreEqual("Child1", copy.Children["Child1"].Name);
    }

    static void SerialiseObject( Object o, String path )
    {
        IFormatter formatter = new BinaryFormatter();
        Stream stream = new FileStream( path, FileMode.Create );
        formatter.Serialize( stream, o );
        stream.Close();
    }
    static Object DeserialiseObject( String path )
    {
        IFormatter formatter = new BinaryFormatter();
        Stream stream = new FileStream( path, FileMode.Open, FileAccess.Read );
        Object o = (Object) formatter.Deserialize( stream );
        stream.Close();
        return o;
    }

    [Serializable]
    private class Parent
    {
        public string Name { get; set; }
        public Dictionary<string, Child> Children { get; protected set; }

        public Parent()
        {
            Children = new Dictionary<string, Child>();
        }
    }

    [Serializable]
    private class Child
    {
        public string Name { get; set; }
    }
}

The children deserialize with the parent and contain the details they were initialized with. I would check any code that is setting your Buses collection. My example just did it in the constructor of the parent class, but it may be possible that you have rogue code setting it after it’s been deserialized?