AttributeTargets AttributeTargets AttributeTargets AttributeTargets Enum

定义

指定可应用属性的应用程序元素。Specifies the application elements on which it is valid to apply an attribute.

此枚举有一个 FlagsAttribute 属性,允许按位组合成员值。

public enum class AttributeTargets
[System.Flags]
[System.Runtime.InteropServices.ComVisible(true)]
[System.Serializable]
public enum AttributeTargets
type AttributeTargets = 
Public Enum AttributeTargets
继承
AttributeTargetsAttributeTargetsAttributeTargetsAttributeTargets
属性

字段

All All All All 32767

可以对任何应用程序元素应用属性。Attribute can be applied to any application element.

Assembly Assembly Assembly Assembly 1

可以对程序集应用属性。Attribute can be applied to an assembly.

Class Class Class Class 4

可以对类应用属性。Attribute can be applied to a class.

Constructor Constructor Constructor Constructor 32

可以对构造函数应用属性。Attribute can be applied to a constructor.

Delegate Delegate Delegate Delegate 4096

可以对委托应用属性。Attribute can be applied to a delegate.

Enum Enum Enum Enum 16

可以对枚举应用属性。Attribute can be applied to an enumeration.

Event Event Event Event 512

可以对事件应用属性。Attribute can be applied to an event.

Field Field Field Field 256

可以对字段应用属性。Attribute can be applied to a field.

GenericParameter GenericParameter GenericParameter GenericParameter 16384

可以对泛型参数应用属性。Attribute can be applied to a generic parameter. 目前,此属性仅可应用于 C#、Microsoft 中间语言 (MSIL) 和已发出的代码中。Currently, this attribute can be applied only in C#, Microsoft intermediate language (MSIL), and emitted code.

Interface Interface Interface Interface 1024

可以对接口应用属性。Attribute can be applied to an interface.

Method Method Method Method 64

可以对方法应用属性。Attribute can be applied to a method.

Module Module Module Module 2

可以对模块应用属性。Attribute can be applied to a module. Module 引用的是可移植可执行文件(.dll 或 .exe),而不是 Visual Basic 标准模块。Module refers to a portable executable file (.dll or.exe) and not a Visual Basic standard module.

Parameter Parameter Parameter Parameter 2048

可以对参数应用属性。Attribute can be applied to a parameter.

Property Property Property Property 128

可以对属性 (Property) 应用属性 (Attribute)。Attribute can be applied to a property.

ReturnValue ReturnValue ReturnValue ReturnValue 8192

可以对返回值应用属性。Attribute can be applied to a return value.

Struct Struct Struct Struct 8

可以对结构应用属性,即值类型。Attribute can be applied to a structure; that is, a value type.

示例

下面的示例说明了到各种目标特性的应用程序。The following example illustrates the application of attributes to various targets.

备注

Visual Basic 和 Visual c + + 语法当前不支持特性的应用程序到类型参数。Visual Basic and Visual C++ syntax currently do not support the application of attributes to type parameters.

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(){}

   };

}

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 a generic type parameter.
    [AttributeUsage(AttributeTargets.GenericParameter)]
    public class GenericParameterTargetAttribute : 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;

        public void GenericMethod<
            [GenericParameterTarget, AllTargets] T>(T x) {
        }

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

注解

AttributeUsageAttribute类使用此枚举可以指定在其上应用属性元素的类型。The AttributeUsageAttribute class uses this enumeration to specify the kind of element on which it is valid to apply an attribute.

AttributeTargets 枚举值可以组合使用位或运算来获得首选的组合。AttributeTargets enumeration values can be combined with a bitwise OR operation to get the preferred combination.

适用于

另请参阅