Why do I need “field:” in my attribute declaration “[field:NonSerialized]”?

Question

I can\'t find \"field\" listed as a C# keyword anywhere. Does anyone know the background on this?

Answer 1

This is meant to allow you to set NonSerialized attribute on fields, this is useful in serializing events.

For instance this would give you a compilation error

[NonSerialized]
public event SomeEventHandler SomeEvent;

To fix this you have to use field:

[field:NonSerialized]
public event SomeEventHandler SomeEvent;

More on this here -- Delegates and Serialization