AttributeTargets Enum

Definition

Namespace:

System

Assembly:

System.Runtime.dll

Specifies the application elements on which it is valid to apply an attribute.

This enumeration supports a bitwise combination of its member values.

public enum class AttributeTargets

[System.Flags]
public enum AttributeTargets

[<System.Flags>]
type AttributeTargets = 

Public Enum AttributeTargets

Inheritance

Object

ValueType

Enum

AttributeTargets

Attributes

FlagsAttribute

Fields

Name	Value	Description
Assembly	1	Attribute can be applied to an assembly.
Module	2	Attribute can be applied to a module. Module refers to a portable executable file (.dll or.exe) and not a Visual Basic standard module.
Class	4	Attribute can be applied to a class.
Struct	8	Attribute can be applied to a structure; that is, a value type.
Enum	16	Attribute can be applied to an enumeration.
Constructor	32	Attribute can be applied to a constructor.
Method	64	Attribute can be applied to a method.
Property	128	Attribute can be applied to a property.
Field	256	Attribute can be applied to a field.
Event	512	Attribute can be applied to an event.
Interface	1024	Attribute can be applied to an interface.
Parameter	2048	Attribute can be applied to a parameter.
Delegate	4096	Attribute can be applied to a delegate.
ReturnValue	8192	Attribute can be applied to a return value.
GenericParameter	16384	Attribute can be applied to a generic parameter. Currently, this attribute can be applied only in C#, Microsoft intermediate language (MSIL), and emitted code.
All	32767	Attribute can be applied to any application element.

Examples

The following example illustrates the application of attributes to various targets.

Note

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) {
        }
    }
}

open System

// This attribute is only valid on a class.
[<AttributeUsage(AttributeTargets.Class)>]
type ClassTargetAttribute() =
    inherit Attribute()

// This attribute is only valid on a method.
[<AttributeUsage(AttributeTargets.Method)>]
type MethodTargetAttribute() =
    inherit Attribute()

// This attribute is only valid on a constructor.
[<AttributeUsage(AttributeTargets.Constructor)>]
type ConstructorTargetAttribute() =
    inherit Attribute()

// This attribute is only valid on a field.
[<AttributeUsage(AttributeTargets.Field)>]
type FieldTargetAttribute() =
    inherit Attribute()

// This attribute is valid on a class or a method.
[<AttributeUsage(AttributeTargets.Class ||| AttributeTargets.Method)>]
type ClassMethodTargetAttribute() =
    inherit Attribute()

// This attribute is valid on a generic type parameter.
[<AttributeUsage(AttributeTargets.GenericParameter)>]
type GenericParameterTargetAttribute() =
    inherit Attribute()

// This attribute is valid on any target.
[<AttributeUsage(AttributeTargets.All)>]
type AllTargetsAttribute() =
    inherit Attribute()

[<ClassTarget>]
[<ClassMethodTarget>]
[<AllTargets>]
type TestClassAttribute [<ConstructorTarget>] [<AllTargets>] () =
    [<FieldTarget>]
    [<AllTargets>]
    let myInt = 0

    [<MethodTarget>]
    [<ClassMethodTarget>]
    [<AllTargets>]
    member _.Method1() = ()

    member _.GenericMethod<[<GenericParameterTarget; AllTargets>] 'T>(x: 'T) = ()

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

Remarks

The AttributeUsageAttribute class uses this enumeration to specify the kind of element on which it is valid to apply an attribute.

AttributeTargets enumeration values can be combined with a bitwise OR operation to get the preferred combination.

See also

• AttributeUsageAttribute