Question

I have this :

    [Flags]
    public enum InfoAbonne{civilite,name,firstname,email,adress,country }

    public class Formulaire
    {
      private InfoAbonne _infoAbonne{ get; set;}
      public Formulaire()
      {}
    }

I want to Xml serialize Formulaire

If I init :
_infoAbonne = InfoAbonne.name | InfoAbonne.email;

In my Xml Result I get only :

<InfoAbonne>email</InfoAbonne>

Answer 1

Even though you added the Flags attribute to your enum, you still need to make sure that the values are powers of two:

[Flags]
public enum InfoAbonne
{
    civilite = 1,
    name = 2,
    firstname = 4,
    email = 8,
    adress = 16,
    country = 32
}

See the guidelines laid out in the Remarks section of the documentation.