How do I use a list / array of some object inheritance with Protobuf / Protobuf-net?
Using Protobuf / Protobuf-net and two classes, one base class and the other derived from base.
How would you serialize / deserialize a list?
For example:
public class SomeBase
{
...
}
public class SomeDerived : SomeBase
{
...
}
And the next serializable field:
public List<SomeBase> SomeList;
Keep in mind that the list contains SomeBase and SomeDerived objects.
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To get this to work, you just need to assign a tag (number) that it will use to identify the subtype. Basically, the protocol buffers explorer specification does not handle inheritance, so protobuf-net achieves this by modeling inheritance as encapsulation. You are assigning properties / fields to tags with [ProtoMember]
and subtyping through [ProtoInclude]
(compare with [XmlInclude]
).
Note that tags must be unique in any one type, but they can be reused in subtypes - as shown in the example by both levels using tag 1.
Same:
using System.Collections.Generic;
using ProtoBuf;
[ProtoContract]
[ProtoInclude(20, typeof(SomeDerived))]
public class SomeBase
{
[ProtoMember(1)]
public string BaseProp { get; set; }
}
[ProtoContract]
public class SomeDerived : SomeBase
{
[ProtoMember(1)]
public int DerivedProp { get; set; }
}
[ProtoContract]
public class SomeEntity
{
[ProtoMember(1)]
public List<SomeBase> SomeList;
}
class Program
{
static void Main()
{
SomeEntity orig = new SomeEntity
{
SomeList = new List<SomeBase> {
new SomeBase { BaseProp = "abc"},
new SomeDerived { BaseProp = "def", DerivedProp = 123}
}
};
var clone = Serializer.DeepClone(orig);
// clone now has a list with 2 items, one each SomeBase and SomeDerived
}
}
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