ProtoBuf、inheritance 和 generics

Question

给定以下代码：

[Serializable, ProtoContract]
[ProtoInclude(100, typeof(ValueA))]
[ProtoInclude(101, typeof(ValueB))]
public class Value
{
}

[Serializable, ProtoContract]
public class ValueA : Value
{
}

[Serializable, ProtoContract]
public class ValueB : Value
{
}

[Serializable, ProtoContract]
[ProtoInclude(1000, typeof(ContainerA))]
[ProtoInclude(1001, typeof(ContainerB))]
public class Container<T> where T : Value
{
    [ProtoMember(1)]
    public T Item;
}

[Serializable, ProtoContract]
public class ContainerA : Container<ValueA>
{
}

[Serializable, ProtoContract]
public class ContainerB : Container<ValueB>
{
}

尝试序列化 ContainerA/ContainerB 时出现错误：

ProtoBuf.ProtoException：ProtoIncludeAttribute 的已知类型 ContainerB 必须是 Container`1 的直接子类

注释掉以下行之一——这样只有一个 class 继承自 Container——将使 ProtoBuf 再次高兴：

[ProtoInclude(1000, typeof(ContainerA))]
[ProtoInclude(1001, typeof(ContainerB))]

这里发生了什么以及可以做些什么？

TIA

Answer 1

我仍在等待更多信息，但最终来自开放通用类型的 inheritance 有点棘手。 也许如果我了解确切的 model 我可以添加更多内容，但以下工作：

using System.Diagnostics;
using ProtoBuf;
[ProtoContract]
[ProtoInclude(1, typeof(ValueA))]
[ProtoInclude(2, typeof(ValueB))]
public class Value
{
}

[ProtoContract]
public class ValueA : Value
{
}

[ProtoContract]
public class ValueB : Value
{
}
[ProtoContract]
[ProtoInclude(1, typeof(Container<ValueA>))]
[ProtoInclude(2, typeof(Container<ValueB>))]
public abstract class Container
{

    public abstract Value BaseValue { get; set; }
}
[ProtoContract]
public class Container<T> : Container where T : Value
{
    [ProtoMember(1)]
    public T Value { get; set;}

    public override Value BaseValue
    {
        get { return Value; }
        set { Value = (T)value; }
    }
}

static class Program
{
    static void Main()
    {
        var model = new Container<ValueA>();
        model.Value = new ValueA();
        var clone = Serializer.DeepClone(model);
        Debug.Assert(clone.Value is ValueA);
    }
}

虽然实际上ValueA和ValueB之间的关系是完全没有必要的，除非你需要它：

using System.Diagnostics;
using ProtoBuf;

[ProtoContract]
public class ValueA
{
}

[ProtoContract]
public class ValueB
{
}

[ProtoContract]
[ProtoInclude(1, typeof(Container<ValueA>))]
[ProtoInclude(2, typeof(Container<ValueB>))]
public abstract class Container
{

    public abstract object BaseValue { get; set; }
}
[ProtoContract]
public class Container<T> : Container
{
    [ProtoMember(1)]
    public T Value { get; set;}

    public override object BaseValue
    {
        get { return Value; }
        set { Value = (T)value; }
    }
}

static class Program
{
    static void Main()
    {
        var model = new Container<ValueA>();
        model.Value = new ValueA();
        var clone = Serializer.DeepClone(model);
        Debug.Assert(clone.Value is ValueA);
    }
}