It's visible in the descriptor for introspection at execution-time - but
it's useful to have the field numbers at *compile* time in order to refer
to them for accessing messages with reflection.
For example, if you have an IMessage which you know represents a Timestamp,
but may be implemented via DynamicMessage (not implemented yet, but
coming...) then it's reasonable to use
long seconds = (long)
message.Descriptor.Fields[Timestamp.SecondsField].Accessor.GetValue(message);
I've considered introducing an enum called Fields as a nested type within
each generated class instead, but that would create unnecessary casting
everywhere.
Jon
On Tuesday, 24 November 2015 20:02:44 UTC, Teddy Zhang wrote:
>
> I notice that for ProtoBuf 3 generated classes, they have fields
> numbers there.
>
> E.g. for C#:
>
>> public const int LatitudeFieldNumber = 1;
>>
>
>
>> private float latitude_;
>> public float Latitude {
>> get { return latitude_; }
>> set {
>> latitude_ = value;
>> }
>> }
>>
>
> Found similar behavior in Java and C++.
>
> I think those should belong to Descriptor, no?
>
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