protobuf-net：如何在消息中表示继承并生成派生 类？

Question

protobuf-net proto2 c#

这是我的 .cs 文件，适用于 protobuf-net serialize/deserialize :

[ProtoBuf.ProtoContract(Name=@"MyBaseTypeProto")]
[ProtoBuf.ProtoInclude(typeof(MyDerivedType), 1)]
public partial class MyBaseType { ... }

[ProtoBuf.ProtoContract(Name=@"MyDerivedTypeProto")] 
public partial class MyDerivedType : MyBaseType { ... }

[ProtoBuf.ProtoContract(Name=@"MyMessageProto")]                                                                  
public partial class MyMessage                                          
{                                                                                               
    [ProtoBuf.ProtoMember(1, IsRequired = false, Name = @"MyList", DataFormat = ProtoBuf.DataFormat.Default)]                                                 
    public List<MyDerivedType> MyList;  

是否可以编写 .proto 文件以便 protogen.exe 生成以上内容？

类似于：

MyBaseType.proto
message MyBaseType {
    ...
}

MyDerivedType.proto
message MyDerivedType {
    ...
}

MyMessage.proto
import "MyDerivedType.proto"
message MyMessage{                                                                          
    repeated MyDerivedType MyList = 1;                                                          
}    

但应用于上述消息类型的 protogen.exe 不会根据需要生成上述 类；具体来说，它不会生成这些代码行：

[ProtoBuf.ProtoInclude(typeof(MyDerivedType), 1)]

public partial class MyDerivedType : MyBaseType

Answer 1

协议缓冲区不支持类似于（或映射到）C++/C# 中直观继承的形式的继承/Java。

见here:

Messages can also be extended, but the method by which this is accomplished differs from familiar C++ or Java-style inheritance. Instead, message extension is implemented by reserving some number of field indices in the base message for use by the extending messages.

protocol buffer docs 说：

Extensions let you declare that a range of field numbers in a message are available for third-party extensions. Other people can then declare new fields for your message type with those numeric tags in their own .proto files without having to edit the original file.

第一篇文章还讨论了其他几种近似多态性的技术，以及每种技术的优缺点。