Serialize Flags enum with two equal values

Question

I want to define a flag enum like the following:

[Flags]
[Serializable]
public enum Numbers
{
    [XmlEnum(Name = "One")]
    One = 0x1,
    [XmlEnum(Name = "Two")]
    Two = 0x2,
    [XmlEnum(Name = "Three")]
    Three = 0x4,
    [XmlEnum(Name = "OddNumbers")]
    OddNumbers = One | Three,
    [XmlEnum(Name = "EvenNumbers")]
    EvenNumbers = Two,
    [XmlEnum(Name = "AllNumbers")]
    AllNumbers = One | Two | Three
}

Suppose I create an object which has a Numbers property and I set that property to EvenNumbers. Today, only Two is included in property, but I want to specify EvenNumbers so that if I add Four in the future it will be included in the property as well.

However, if I serialize this object using XmlSerializer.Serialize, the XML will say Two because today this is the same underlying value.

How can I force the serializer to serialize this property as EvenNumbers?

Answer 1

Do something like that: Mark the Number property as XmlIgnore and create another property type of string for return the string value of enum.

[Serializable]
public class NumberManager
{
    [XmlIgnore]
    public Numbers Numbers { get; set; }

    [XmlAttribute(AttributeName="Numbers")]
    public string NumbersString
    {
        get { return Numbers.ToString(); }
        set { Numbers = (Numbers) Enum.Parse(typeof (Numbers), value); }
    }
}

Then serialize the NumberManager.

I hope it helps.