gistfile1.cs

void write(entity e, BinaryWriter w)
{
    w.write(e.Template.Id);
    foreach (Component c in e.Components) //e.Components is ordered in a specific way when it's constructed
    {
        Assert(e.Template.Contains(c));
        c.Write(w); //Component writes out the data it needs
    }
}

Entity Read(BinaryReader r)
{
    Template t = Template.GetById(r.ReadInt());
    foreach (Action constructorAction in t.Components) //Reflection of constructor is done at template construction time (load time)
    {
        constructorAction(r); //Component reads the data is needs in the constructor which accepts a BinaryReader
    }
}

class ExampleComponent
{
    int SomeData;
    string ImportantState;

    ExampleComponent(int data, string state)
    {
        SomeData = data;
        ImportantState = state;
    }

    ExampleComponent(BinaryReader r)
        :this(r.ReadInt(), r.ReadString())
    {
    }

    override void Write(BinaryWriter w)
    {
        r.WriteInt(SomeData);
        r.WriteString(ImportantState);
    }
}