Error while using ProtoBuf-Net with flags enum

Question

While using ProtoBuf-Net and serializing an enum property, where the enum is set to [FlagsAttribute], I received the following error message when serializing an enum value c

Answer 1

Update : this is now fixed in r274; you would use:

[ProtoMember(12, DataFormat = DataFormat.TwosComplement)]
public MyEnum MyValue {get;set;}

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Ultimately the protocol buffers wire format doesn't provide any scope for [Flags] enums - it enforces enum values against the discreet set. I could allow this easily enugh, but:

• I'd probably have to disable enum mappings in this case, or do a lot of ugly bit- matching work
• it would not be strictly compatible

An easier way of doing this may be to do a shim in your code:

public MyEnum MyValue {get;set;}
[ProtoMember(12)]
private int MyValueWire {
    get {return (int)MyValue;}
    set {MyValue = (MyEnum)value;}
}

The other alternative would be to add a flag that works like the above on your behalf; treating it as an int rather than an enum.