CODEWITHSUNDEEP
c#inheritanceserializationprotocol-buffersprotobuf-net
BaltoStar
BaltoStar

Reputation: 8987

protobuf-net : how to annotate properties of derived type?

For the latest version of protobuf-net ( r640 folder ), how to best annotate a ProtoMember that is a derived type ?

[ProtoBuf.ProtoContract(Name=@"MyBaseTypeProto")]                                       
[Serializable]      
public partial class MyBaseType: ProtoBuf.IExtensible { ... }

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

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

I've tried adding DynamicType property to the ProtoMember attribute but it's not recognized.

I require a solution where the classes can be generated from xml defs of proto types. So ideally this would be done via attributes annotated onto properties definitions.

It would seem possible to use protogen.exe to generate classes based on message-type defs ( .proto files ) that include import statements : 

package MyPackage;                                                          

import "MyDerivedTypeProto.proto";                                                          

message MyMessage{                                                                          
    repeated MyDerivedType MyList = 1;                                                          
}

but the import statements apparently have no effect on the generated C# classes ( .cs files ) except to add a comment :

// Generated from: MyMessageProto.proto
// Note: requires additional types generated from: MyDerivedType.proto

Upvotes: 3

Views: 1044

Answers (1)

Marc Gravell
Marc Gravell

Reputation: 1062975

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

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

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

Should do it (untested, not by a suitable computer). The key addition is the [ProtoInclude] on the base-type. I removed [Serializable] because protobuf-net really doesn't care about that.

Upvotes: 1

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