Kenton is of course quite correct. There is no *native* distinction between a null list and an empty list in the raw protobuf data stream. There *are* some ways of working around that, to distinguish between the two, but not when using the code-generation from .proto.
Marc On 22 June 2010 18:59, Kenton Varda <[email protected]> wrote: > Protocol Buffers has no concept of "null". Lists can be empty, but not > "null". > > > On Mon, Jun 21, 2010 at 6:35 PM, Manh Do <[email protected]> wrote: > >> I am working a project where we need to determine if a protobuf list >> have is null or not in the protocol buffer. >> >> The problem is the generated c# automatically instantiates the list. >> >> IE. Protocol: >> message B { >> repeated A MyList = 0; >> } >> >> Generated C#: >> >> private readonly global::System.Collections.Generic.List<A> _MyList = >> new global::System.Collections.Generic.List<A>(); >> [global::ProtoBuf.ProtoMember(0, Name=@"MyList", DataFormat = >> global::ProtoBuf.DataFormat.Default)] >> public global::System.Collections.Generic.List<A> MyList >> { >> get { return _MyList ; } >> } >> >> The problem with this is I cannot determine if the list is null. I am >> using an empty list as a way to remove all objects. >> >> Is there a way where I can make the generator not automatically >> instantiate the list? Better yet, how do I check for default values in >> protocol buffer C#? I know you can check for >> 'default(typeof(MyType));'. >> >> Thanks for the help! >> >> -Manh >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Protocol Buffers" group. >> To post to this group, send email to [email protected]. >> To unsubscribe from this group, send email to >> [email protected]<protobuf%[email protected]> >> . >> For more options, visit this group at >> http://groups.google.com/group/protobuf?hl=en. >> >> > -- > You received this message because you are subscribed to the Google Groups > "Protocol Buffers" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]<protobuf%[email protected]> > . > For more options, visit this group at > http://groups.google.com/group/protobuf?hl=en. > -- Regards, Marc -- You received this message because you are subscribed to the Google Groups "Protocol Buffers" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/protobuf?hl=en.
