AttributeTargets 枚举

指定可以对它们应用属性的应用程序元素。

此枚举有一个 FlagsAttribute 属性，允许其成员值按位组合。

**命名空间:**System
**程序集:**mscorlib（在 mscorlib.dll 中）

语法

声明
<SerializableAttribute> _
<ComVisibleAttribute(True)> _
<FlagsAttribute> _
Public Enumeration AttributeTargets
用法
Dim instance As AttributeTargets

[SerializableAttribute] 
[ComVisibleAttribute(true)] 
[FlagsAttribute] 
public enum AttributeTargets

[SerializableAttribute] 
[ComVisibleAttribute(true)] 
[FlagsAttribute] 
public enum class AttributeTargets

/** @attribute SerializableAttribute() */ 
/** @attribute ComVisibleAttribute(true) */ 
/** @attribute FlagsAttribute() */ 
public enum AttributeTargets

SerializableAttribute 
ComVisibleAttribute(true) 
FlagsAttribute 
public enum AttributeTargets

成员

	成员名称	说明
	All	可以对任何应用程序元素应用属性。
	Assembly	可以对程序集应用属性。
	Class	可以对类应用属性。
	Constructor	可以对构造函数应用属性。
	Delegate	可以对委托应用属性。
	Enum	可以对枚举应用属性。
	Event	可以对事件应用属性。
	Field	可以对字段应用属性。
	GenericParameter	可以对泛型参数应用属性。
	Interface	可以对接口应用属性。
	Method	可以对方法应用属性。
	Module	可以对模块应用属性。  提示 Module 指的是可移植的可执行文件（.dll 或 .exe），而非 Visual Basic 标准模块。
	Parameter	可以对参数应用属性。
	Property	可以对属性 (Property) 应用属性 (Attribute)。
	ReturnValue	可以对返回值应用属性。
	Struct	可以对结构应用属性，即值类型。

备注

AttributeTargets 用作 AttributeUsageAttribute 的参数，以指定可以对其应用属性的元素类型。

可以通过按位“或”运算组合 AttributeTargets 枚举值来获得首选组合。

示例

下面的代码示例演示如何应用 AttributeTargets 枚举：

Imports System

Module DemoModule
    ' This attribute is only valid on a class.
    <AttributeUsage(AttributeTargets.Class)> _
    Public Class ClassTargetAttribute
        Inherits Attribute
    End Class

    ' This attribute is only valid on a method.
    <AttributeUsage(AttributeTargets.Method)> _
    Public Class MethodTargetAttribute
        Inherits Attribute
    End Class

    ' This attribute is only valid on a constructor.
    <AttributeUsage(AttributeTargets.Constructor)> _
    Public Class ConstructorTargetAttribute 
        Inherits Attribute
    End Class

    ' This attribute is only valid on a field.
    <AttributeUsage(AttributeTargets.Field)> _
    Public Class FieldTargetAttribute 
        Inherits Attribute
    End Class

    ' This attribute is valid on a class or a method.
    <AttributeUsage(AttributeTargets.Class Or AttributeTargets.Method)> _
    Public Class ClassMethodTargetAttribute 
        Inherits Attribute
    End Class

    ' This attribute is valid on any target.
    <AttributeUsage(AttributeTargets.All)> _
    Public Class AllTargetsAttribute 
        Inherits Attribute
    End Class

    <ClassTarget, _
    ClassMethodTarget, _
    AllTargets> _
    Public Class TestClassAttribute
        <ConstructorTarget, _
        AllTargets> _
        Public Sub New
        End Sub

        <MethodTarget, _
        ClassMethodTarget, _
        AllTargets> _
        Public Sub Method1()
        End Sub

        <FieldTarget, _
        AllTargets> _
        Public myInt as Integer
    End Class

    Sub Main()
    End Sub
End Module

using System;

namespace AttTargsCS {
    // This attribute is only valid on a class.
    [AttributeUsage(AttributeTargets.Class)]
    public class ClassTargetAttribute : Attribute {
    }

    // This attribute is only valid on a method.
    [AttributeUsage(AttributeTargets.Method)]
    public class MethodTargetAttribute : Attribute {
    }

    // This attribute is only valid on a constructor.
    [AttributeUsage(AttributeTargets.Constructor)]
    public class ConstructorTargetAttribute : Attribute {
    }

    // This attribute is only valid on a field.
    [AttributeUsage(AttributeTargets.Field)]
    public class FieldTargetAttribute : Attribute {
    }

    // This attribute is valid on a class or a method.
    [AttributeUsage(AttributeTargets.Class|AttributeTargets.Method)]
    public class ClassMethodTargetAttribute : Attribute {
    }

    // This attribute is valid on any target.
    [AttributeUsage(AttributeTargets.All)]
    public class AllTargetsAttribute : Attribute {
    }

    [ClassTarget]
    [ClassMethodTarget]
    [AllTargets]
    public class TestClassAttribute {
        [ConstructorTarget]
        [AllTargets]
        TestClassAttribute() {
        }

        [MethodTarget]
        [ClassMethodTarget]
        [AllTargets]
        public void Method1() {
        }

        [FieldTarget]
        [AllTargets]
        public int myInt;

        static void Main(string[] args) {
        }
    }
}

using namespace System;

namespace AttTargsCS
{

   // This attribute is only valid on a class.

   [AttributeUsage(AttributeTargets::Class)]
   public ref class ClassTargetAttribute: public Attribute{};


   // This attribute is only valid on a method.

   [AttributeUsage(AttributeTargets::Method)]
   public ref class MethodTargetAttribute: public Attribute{};


   // This attribute is only valid on a constructor.

   [AttributeUsage(AttributeTargets::Constructor)]
   public ref class ConstructorTargetAttribute: public Attribute{};


   // This attribute is only valid on a field.

   [AttributeUsage(AttributeTargets::Field)]
   public ref class FieldTargetAttribute: public Attribute{};


   // This attribute is valid on a class or a method.

   [AttributeUsage(AttributeTargets::Class|AttributeTargets::Method)]
   public ref class ClassMethodTargetAttribute: public Attribute{};


   // This attribute is valid on any target.

   [AttributeUsage(AttributeTargets::All)]
   public ref class AllTargetsAttribute: public Attribute{};


   [ClassTarget]
   [ClassMethodTarget]
   [AllTargets]
   public ref class TestClassAttribute
   {
   private:

      [ConstructorTarget]
      [AllTargets]
      TestClassAttribute(){}


   public:

      [MethodTarget]
      [ClassMethodTarget]
      [AllTargets]
      void Method1(){}


      [FieldTarget]
      [AllTargets]
      int myInt;
      static void Main(){}

   };

}

package AttTargsJSL;
import System.*;

// This attribute is only valid on a class.
/** @attribute AttributeUsage(AttributeTargets.Class)
 */
public class ClassTargetAttribute extends Attribute
{
} //ClassTargetAttribute

// This attribute is only valid on a method.
/** @attribute AttributeUsage(AttributeTargets.Method)
 */
public class MethodTargetAttribute extends Attribute
{
} //MethodTargetAttribute

// This attribute is only valid on a constructor.
/** @attribute AttributeUsage(AttributeTargets.Constructor)
 */
public class ConstructorTargetAttribute extends Attribute
{
} //ConstructorTargetAttribute

// This attribute is only valid on a field.
/** @attribute AttributeUsage(AttributeTargets.Field)
 */
public class FieldTargetAttribute extends Attribute
{
} //FieldTargetAttribute

// This attribute is valid on a class or a method.
/** @attribute AttributeUsage(AttributeTargets.Class | AttributeTargets.Method)
 */
public class ClassMethodTargetAttribute extends Attribute
{
} //ClassMethodTargetAttribute

// This attribute is valid on any target.
/** @attribute AttributeUsage(AttributeTargets.All)
 */
public class AllTargetsAttribute extends Attribute
{
} //AllTargetsAttribute

/** @attribute ClassTarget()
 */
/** @attribute ClassMethodTarget()
 */
/** @attribute AllTargets()
 */
public class TestClassAttribute
{
    /** @attribute.ConstructorTarget ConstructorTarget()
     */
    /** @attribute AllTargets()
     */
    TestClassAttribute()
    {
    } //TestClassAttribute

    /** @attribute MethodTarget()
     */
    /** @attribute ClassMethodTarget()
     */
    /** @attribute AllTargets()
     */
    public void Method1()
    {
    } //Method1

    /** @attribute FieldTarget()
     */
    /** @attribute AllTargets()
     */
    public int myInt;

    public static void main(String[] args)
    {
    } //main
} //TestClassAttribute

import System;

package AttTargsJS {
    // This attribute is only valid on a class.
    AttributeUsage(AttributeTargets.Class)
    public class ClassTargetAttribute extends Attribute {
    }

    // This attribute is only valid on a method.
    AttributeUsage(AttributeTargets.Method)
    public class MethodTargetAttribute extends Attribute {
    }

    // This attribute is only valid on a constructor.
    AttributeUsage(AttributeTargets.Constructor)
    public class ConstructorTargetAttribute extends Attribute {
    }

    // This attribute is only valid on a field.
    AttributeUsage(AttributeTargets.Field)
    public class FieldTargetAttribute extends Attribute {
    }

    // This attribute is valid on a class or a method.
    AttributeUsage(AttributeTargets.Class|AttributeTargets.Method)
    public class ClassMethodTargetAttribute extends Attribute {
    }

    // This attribute is valid on any target.
    AttributeUsage(AttributeTargets.All)
    public class AllTargetsAttribute extends Attribute {
    }

    ClassTargetAttribute
        ClassMethodTargetAttribute
        AllTargetsAttribute
    public class TestClassAttribute {
        ConstructorTargetAttribute
        AllTargetsAttribute
        function TestClassAttribute() {
        }

        MethodTargetAttribute
                ClassMethodTargetAttribute
                AllTargetsAttribute
        public function Method1() {
        }

        FieldTargetAttribute
                AllTargetsAttribute
        public var myInt : int;

        static function Main(args : String[]) {
        }
    }
}

平台

Windows 98、Windows 2000 SP4、Windows CE、Windows Millennium Edition、Windows Mobile for Pocket PC、Windows Mobile for Smartphone、Windows Server 2003、Windows XP Media Center Edition、Windows XP Professional x64 Edition、Windows XP SP2、Windows XP Starter Edition

.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表，请参见系统要求。

版本信息

.NET Framework

受以下版本支持：2.0、1.1、1.0

.NET Compact Framework

受以下版本支持：2.0、1.0

请参见

参考

System 命名空间
AttributeUsageAttribute