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

The C# compiler usually has no trouble figuring out what part of a declaration the attribute applies to. I can think of three cases where you might use it:

1. Attributes that apply to the assembly. Very visible in AssemblyInfo.cs
2. An attribute applied to the return value of a P/Invoke declaration, [return:MarshalAs]
3. Having the attribute apply to the backing variable of a property or event without accessors. Your case.