C# 0 The Complete Reference

PART I

C h a p t e r   1 7 :  

R u n t i m e   T y p e   I D ,   R e f l e c t i o n ,   a n d   A t t r i b u t e s  

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PART IPART I

One last point: For both positional and named parameters, the type of an attribute 

parameter must be either one of the built-in primitive types, 

object

,

Type

, an enumeration, 

or a one-dimensional array of one of these types.

Three Built-in Attributes

C# defines several built-in attributes, but three are especially important because they apply 

to a wide variety of situations: 

AttributeUsage

,

Conditional

, and 

Obsolete

. They are 

examined here.

AttributeUsage

As mentioned earlier, the 

AttributeUsage

 attribute specifies the types of items to 

which an attribute can be applied. 

AttributeUsage

 is another name for the