This is specifically a protobuf-net question.
In short, yes - that is fine... ish. If you add the numbers manually ***and
get them right***, then it will work. However, your example actually gets
them wrong: the protobuf-net library specifically assumes an *alphabetical*
order for the properties / fields when using ImplicitFields, because
reflection does not guarantee any particular order - see the "Remarks"
section on MSDN: http://msdn.microsoft.com/en-us/library/6ztex2dc.aspx and
http://msdn.microsoft.com/en-us/library/kyaxdd3x.aspx
So the order is actually: Id = 1, IsAvailable = 2, Name = 3, Quantity = 4 -
you would then add NewField1 and NewField2 as 5 and 6, presumably.
Just to quote from the documentation on ImplicitFields, too:
/// <summary>
/// Specifies the method used to infer field tags for members of the type
/// under consideration. Tags are deduced using the invariant alphabetic
/// sequence of the members' names; this makes implicit field tags
very brittle,
/// and susceptible to changes such as field names (normally an isolated
/// change).
/// </summary>
Marc
(protobuf-net)
On 15 July 2013 06:48, Pravesh Tanwar <[email protected]> wrote:
> Hi All,
>
> I am currently using Protobuf serializer in my C# project. Currently I am
> serializing my Objects using "
> [ProtoContract(ImplicitFields = ImplicitFields.AllPublic)]". The
> serialized objects are stored in database and deserialized when needed. I
> have now landed in a position that requires me to add new DataMembers to
> existing object. I want to be able to do this without breaking backward
> compatibility (while deserializing) of my current serialized objects.
>
> Is there a way for me to check what order does the Protobuf
> serialize/deserialize objects?
>
> e.g of the Object being serialized:
>
> [ProtoContract(ImplicitFields = ImplicitFields.AllPublic)]
>
> public class Product
> {
> [DataMember]
> public int Id { get; set; }
>
> [DataMember]
> public string Name { get; set; }
>
> [DataMember]
> public double Quantity { get; set; }
>
>
>
> [DataMember]
> public bool? IsAvailable { get; set; }
>
> }
>
> If I can know what order they are currently being serialized then I can
> use the "Order" data member attribute and make sure that the additional
> fields are ordered at the end. Hopefully this will retain backward
> compatibility while deserializing. e.g:
>
>
> public class Product
>
> {
> [DataMember(Order = 1)]
>
> public int Id { get; set; }
>
>
> [DataMember(Order = 2)]
>
> public double Quantity { get; set; }
>
>
> [DataMember(Order = 3)]
>
>
> public bool? IsAvailable { get; set; }
>
>
> [DataMember(Order = 4)]
>
> public string Name { get; set; }
>
>
> [DataMember(Order = 5)]
>
> public string NewField1 { get; set; }
>
>
> [DataMember(Order = 6)]
>
> public string NewField2 { get; set; }
>
> }
>
>
> Any ideas?
>
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>
--
Regards,
Marc
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