C# @ in enum generated classes from XSD

Question

Using xsd.exe I've got an enum which has an @ symbol in front of one of the elements. I can't work out why, and I can't work out what it's for or what it means. Searching Google for a symbol isn't terribly productive.

Original XSD fragment:

  <xs:simpleType name="stopLocation">
    <xs:restriction base="xs:string">
      <xs:enumeration value="default"/>
      <xs:enumeration value="near"/>
      <xs:enumeration value="far"/>
      <xs:enumeration value="nearExact"/>
      <xs:enumeration value="farExact"/>
    </xs:restriction>
  </xs:simpleType>

Generated class fragment:

public enum stopLocation {
    @default,
    near,
    far,
    nearExact,
    farExact,
}

(Yes, the final element has a comma which VS seems happy with)

Thanks.

`default` is a reserved keyword; the `@` prefacing a reserved keyword lets you use it as a legal identifier (using it is a smell IMO (especially the disgusting `@this`)). The seemingly-extraneous `,` is legal as per the specification. It makes code maintenance and code generation a little bit easier. — jason, Aug 29 '11 at 19:54
Ah, I was focusing on the @ being part of the enum rather than as a language feature - makes sense now! I'd never had the need to use it, hence not knowing it until now. I'll see if I can get the inherited XSD changed. Thanks everyone. — GeoffM, Aug 29 '11 at 20:03

score 5 · Accepted Answer · edited May 23 '17 at 12:19

5

It escapes the default keyword from C#.

See this question: What's the use/meaning of the @ character in variable names in C#?

edited May 23 '17 at 12:19

Community

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answered Aug 29 '11 at 19:51

Daniel A. White

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score 1 · Answer 2 · answered Aug 29 '11 at 19:52

1

This is happening because the enum value name (default) is a reserved word. In C# reserved words must be appended with an @ so the compiler knows how to interpret them.

You would see the same behavior with a name like 'event' or 'public'.

answered Aug 29 '11 at 19:52

Nathan Taylor

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score 1 · Answer 3 · answered Aug 29 '11 at 19:52

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default is a C# keyword.

The @ symbol is used as a way to escape language keywords so that they can be used as variable names and other identifiers.

answered Aug 29 '11 at 19:52

Daniel Schaffer

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score 0 · Answer 4 · answered Aug 29 '11 at 19:52

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http://dotnetdud.blogspot.com/2008/12/how-to-use-reserved-words-in-net-c.html

The "@" syntax allows you to use a reserved language word as a variable/member name. I would consider it poor practice in most cases.

answered Aug 29 '11 at 19:52

Tim M.

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C# @ in enum generated classes from XSD

4 Answers4