The following are the predefined attributes in C# −
The pre-defined attribute AttributeUsage describes how a custom attribute class can be used. Here is the syntax −
[AttributeUsage ( validon, AllowMultiple = allowmultiple, Inherited = inherited )]
This predefined attribute marks a conditional method whose execution depends on a specified preprocessing identifier. It causes conditional compilation of method calls, depending on the specified value such as Debug or Trace.
The following is the syntax −
[Conditional( conditionalSymbol )]
This predefined attribute marks a program entity that should not be used. It enables you to inform the compiler to discard a particular target element. Here is the syntax −
[Obsolete ( message )] [Obsolete ( message, iserror )]