Protobuf网络和流:未设置流时出现InvalidCastException.位置=0

如果我想用protobuf-net反序列化，为什么我必须手动将序列化对象的流位置设置为0？

我希望protobuf-net总是从一开始就读取我的输入流。

如果我想让protobuf-net从不同的偏移位置读取我的流（比如通过标签读取类或列表的成员），我会认为这将是一个特殊的用例，我必须有意识地以不同的方式处理它（api方式）。

（我的protobuf网络版本是640。）

这是我的测试用例，它使用继承引发了一个异常：

using System.IO;
using ProtoBuf;
namespace ProtobufStreamTest
{
    public class Class1
    {
        static public void Main(string[] args)
        {
            var inheritingModel = new InheritingModel()
            {
                InheritingModelMember1 = "testinheriting",
                BaseModelMember1 = 42,
            };
            var ms = new MemoryStream();
            ProtoBuf.Serializer.Serialize(ms, inheritingModel);
            var originalStreamPos = ms.Position; // == 33
            // ms.Position = 0; // <== works okay, but why do I have to do this? Not setting position = 0 raises InvalidCastException: Unable to cast object of type 'ProtobufStreamTest.BaseModel' to type 'ProtobufStreamTest.InheritingModel'
            var deserialized = ProtoBuf.Serializer.Deserialize<InheritingModel>(ms);
            ms.Close();
        }
    }
    [ProtoContract]
    public class InheritingModel : BaseModel
    {
        [ProtoMember(4)]
        public string InheritingModelMember1 { get; set; }
    }
    [ProtoContract]
    [ProtoInclude(1, typeof(InheritingModel))]
    public class BaseModel
    {
        [ProtoMember(2)]
        public int BaseModelMember1 { get; set; }
    }
}

此测试用例不引发异常，不涉及继承，但反序列化对象具有默认（null）值：

using System.IO;
using ProtoBuf;
namespace ProtobufStreamTest
{
    public class Class1
    {
        static public void Main(string[] args)
        {
            var inheritingModel = new InheritingModel()
            {
                InheritingModelMember1 = "testinheriting",
            };
            var ms = new MemoryStream();
            ProtoBuf.Serializer.Serialize(ms, inheritingModel);
            var originalStreamPos = ms.Position; // == 16
            // ms.Position = 0; // works okay, but why do I have to do this? Not setting position to null results in a deserialized object but with null member values
            var deserialized = ProtoBuf.Serializer.Deserialize<InheritingModel>(ms);
            ms.Close();
        }
    }
    [ProtoContract]
    public class InheritingModel
    {
        [ProtoMember(1)]
        public string InheritingModelMember1 { get; set; }
    }
}