类调用Serialize时会尝试强制转换为self

Question

我有以下基本代码：

[Serializable]
[ProtoContract(ImplicitFields = ImplicitFields.AllFields, SkipConstructor = true, InferTagFromName = true, UseProtoMembersOnly = false,ImplicitFirstTag=10)]
public class BaseCustomDictionary<TKey, TValue>
{
    [NonSerialized]
    [ProtoIgnore]
    private System.Collections.Generic.Dictionary<TKey, System.Collections.ObjectModel.Collection<TValue>> collection;

    private System.Collections.Generic.Dictionary<TKey, TValue[]> serializationCollection;

    [OnSerializing]
    [ProtoBeforeSerialization]
    private void OnSerializing(StreamingContext context)
    {
        serializationCollection = System.Collections.Generic.Dictionary<TKey, TValue[]>();
        foreach (KeyValuePair<TKey, System.Collections.ObjectModel.Collection<TValue>> values in collection)
        {
            TValue[] array = new TValue[values.Value.Count];
            values.CopyTo(array, 0);
            serializationCollection.Add(values.Key, array);
        }
    }

    [OnDeserialized]
    [ProtoAfterDeserialization]
    private void OnDeserialized(StreamingContext context)
    {
        collection = new System.Collections.Generic.Dictionary<TKey, System.Collections.ObjectModel.Collection<TValue>>();
        foreach (KeyValuePair<TKey, TValue[]> value in serializationCollection)
        {
            foreach (TValue v in value.Value)
            {
                Add(value.Key, v);
            }
        }
        serializationCollection = null;
    }

    public BaseCustomDictionary()
    {
        collection = System.Collections.Generic.new Dictionary<TKey, System.Collections.ObjectModel.Collection<TValue>>();

        MetaType metaType = RuntimeTypeModel.Default[typeof(BaseCustomDictionary<TKey, TValue>)];
        metaType.AddSubType(1, typeof(DerivedCustomDictionary<TKey, TValue>));
    }

    public void Add(TKey key, TValue value)
    {
        if (!collection.ContainsKey(key))
        {
            collection.Add(key, CreateCollection());
        }
        collection[key].Add(value)
    }

    public virtual System.Collections.ObjectModel.Collection<TValue> CreateCollection()
    {
        return new System.Collections.ObjectModel.Collection<TValue>();
    }
}

[Serializable]
[ProtoContract(ImplicitFields = ImplicitFields.AllFields, SkipConstructor = true, InferTagFromName = true, UseProtoMembersOnly = false, ImplicitFirstTag=10)]
public class DerivedCustomDictionary<TKey, TValue>
{
    public override System.Collections.ObjectModel.Collection<TValue> CreateCollection()
    {
        return new System.Collections.ObjectModel.ObservableCollection<TValue>();
    }
}

[ProtoContract(...)]
[ProtoInclude(1, typeof(DerivedClass))]
public abstract class SomeClass
{
    private DerivedCustomDictionary<System.Type, SomeClass> children = new DerivedCustomDictionary<System.Type, SomeClass>();

    public DerivedCustomDictionary<System.Type, SomeClass> Children
    {
        get
        {
            return children;
        }
    }
}

public class DerivedClass : SomeClass
{
    public string Text
    {
        get;
        set;
    }
}

DerivedClass root = new DerivedClass();
//ADD CHILDREN THAT HAVE CHILDREN ETC.
using(FileStream stream = new FileStream("Path", FileMode.Create, FileAccess.Write, FileShare.Read))
{
    Serializer.Serialize(stream, root)
}

当我致电Serializer.Serialize(stream, root)时，我收到一个错误，因为它试图将“儿童”的类型转换为BaseClass而不会令人震惊地失败。