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Attribute特性，可以往程序集中写入一些元数据。微软类库中自带很多 Attribute类，某些时候，需要对类标注一下 Attribute。那么自定义 Attribute的用处是什么的，或者说，什么时候我们需要自定义 Attribute。
在我看来， 自定义Attribute没啥用。常规的项目开发中，我都可以用变通的方式去实现。当然硬是要为了用而用也可以，就是写一些信息到程序集中，然后在调用的时候在读取这些信息。采用反射的技术，但这不是多此一举影响性能么，直接把信息传给类不更好吗？ 所以不清楚何时何地必须要Attribute。下面的例子，就是，用到反射读取Attribute的信息。 using System ; using System.Collections.Generic ; using System.Linq ; using System.Text ; using System.Dynamic ; namespace ConsoleApplication1
{ class Program
{ // create custom attribute to be assigned to class members [AttributeUsage
(AttributeTargets
. Class | AttributeTargets
. Constructor | AttributeTargets
. Field | AttributeTargets
. Method | AttributeTargets
. Property,
AllowMultiple
= true ) ] public class BugFixAttribute
: System . Attribute { // attribute constructor for positional parameters public BugFixAttribute
( int bugID,
string programmer,
string date
) { this . BugID = bugID
; this . Programmer = programmer
; this . Date = date
; } // accessors public int BugID
{ get
; private set
; } public string Date
{ get
; private set
; } public string Programmer
{ get
; private set
; } // property for named parameter public string Comment
{ get
; set
; } } // ********* assign the attributes to the class ******** [BugFixAttribute
( 121,
"Jesse Liberty",
"01/03/08" ) ] [BugFixAttribute
( 107,
"Jesse Liberty",
"01/04/08",
Comment
= "Fixed off by one errors" ) ] public class MyMath
{ public double DoFunc1
( double param1
) { return param1
+ DoFunc2
(param1
) ; } public double DoFunc2
( double param1
) { return param1
/ 3 ; } } public class Tester
{ static void Main
( string [ ] args
) { MyMath mm
= MyMath
( ) ; Console
. WriteLine ( "Calling DoFunc(7). Result: {0}",
mm
. DoFunc1 ( 7 ) ) ; // get the member information and use it to // retrieve the custom attributes System.Reflection . MemberInfo inf
= (MyMath
) ; object [ ] attributes
; attributes
= inf
. GetCustomAttributes ( (BugFixAttribute
),
false ) ; // iterate through the attributes, retrieving the // properties foreach ( Object attribute
in attributes
) { BugFixAttribute bfa
= (BugFixAttribute
)attribute
; Console
. WriteLine ( "\nBugID: {0}", bfa
. BugID ) ; Console
. WriteLine ( "Programmer: {0}", bfa
. Programmer ) ; Console
. WriteLine ( "Date: {0}", bfa
. Date ) ; Console
. WriteLine ( "Comment: {0}", bfa
. Comment ) ; } } } } } 转载地址：http://pcbmx.baihongyu.com/