Are Enums binary serialized as numbers or as text - I want to rename them

Question

Are Enums binary serialized as numbers or as text - I want to rename them.

Example:

[Flags]
public enum VerticalAlignment : byte
{
    None = 0,
    Centered = 1,
    Top = 2,
    Bottom = 4,
    Stretch = 8,
    All = Centered | Top | Bottom | Stretch
}

Answer 1

It depends on the serializer you are using.

Here is code that uses the DataContractSerializer

var serializer = new DataContractSerializer(typeof (VerticalAlignment));

var alignment = VerticalAlignment.Centered;

using (var stream = File.Create("serialize.txt"))
{
    serializer.WriteObject(stream, alignment);
    stream.Close();
}

This will serialize the data as XML, which uses the enum's name and not the value. The contents of the "serialize.txt" file are as follows:

<Program.VerticalAlignment xmlns="http://schemas.datacontract.org/2004/07/ConsoleApplication2">Centered</Program.VerticalAlignment>

If you want to do binary serialization, you can use the BinaryFormatter class:

var serializer = new BinaryFormatter();

var alignment = VerticalAlignment.Centered;

using (var stream = File.Create("serialize.txt"))
{
    serializer.Serialize(stream, alignment);
    stream.Close();
}

This will write the following to our serialization file:

To test if name or value is used, we can rename the field and see if what gets written to file is different. First, we rename the enum field:

[Flags]
public enum VerticalAlignment : byte
{
    None = 0,
    CenteredDummy = 1,
    Top = 2,
    Bottom = 4,
    Stretch = 8,
    All = CenteredDummy | Top | Bottom | Stretch
}

Now, if we examine the data that was written to file, we can see that the contents are the same:

We thus now know for sure that the enum value is used and not the key.