Specifies the usage of another attribute class. This class cannot be inherited.
System.Attribute
System.AttributeUsageAttribute
Namespace: System
Assembly: mscorlib (in mscorlib.dll)
<SerializableAttribute> _ <AttributeUsageAttribute(AttributeTargets.Class, Inherited := True)> _ <ComVisibleAttribute(True)> _ Public NotInheritable Class AttributeUsageAttribute _ Inherits Attribute
[SerializableAttribute] [AttributeUsageAttribute(AttributeTargets.Class, Inherited = true)] [ComVisibleAttribute(true)] public sealed class AttributeUsageAttribute : Attribute
[SerializableAttribute] [AttributeUsageAttribute(AttributeTargets::Class, Inherited = true)] [ComVisibleAttribute(true)] public ref class AttributeUsageAttribute sealed : public Attribute
[<Sealed>] [<SerializableAttribute>] [<AttributeUsageAttribute(AttributeTargets.Class, Inherited = true)>] [<ComVisibleAttribute(true)>] type AttributeUsageAttribute = class inherit Attribute end
The AttributeUsageAttribute type exposes the following members.
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AttributeUsageAttribute | Initializes a new instance of the AttributeUsageAttribute class with the specified list of AttributeTargets, the AllowMultiple value, and the Inherited value. |
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AllowMultiple | Gets or sets a Boolean value indicating whether more than one instance of the indicated attribute can be specified for a single program element. |
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Inherited | Gets or sets a Boolean value indicating whether the indicated attribute can be inherited by derived classes and overriding members. |
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TypeId | When implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute.) |
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ValidOn | Gets a set of values identifying which program elements that the indicated attribute can be applied to. |
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Equals | Infrastructure. Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute.) |
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Finalize | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.) |
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GetHashCode | Returns the hash code for this instance. (Inherited from Attribute.) |
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GetType | Gets the Type of the current instance. (Inherited from Object.) |
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IsDefaultAttribute | When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute.) |
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Match | When overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.) |
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MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) |
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ToString | Returns a string that represents the current object. (Inherited from Object.) |
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_Attribute.GetIDsOfNames | Maps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.) |
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_Attribute.GetTypeInfo | Retrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.) |
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_Attribute.GetTypeInfoCount | Retrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.) |
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_Attribute.Invoke | Provides access to properties and methods exposed by an object. (Inherited from Attribute.) |
When you are defining your own attribute class, you can control the manner in which it is used by placing an AttributeUsageAttribute on your attribute class. The indicated attribute class must derive from Attribute, either directly or indirectly.
Attribute classes have positional and named parameters. Each public constructor for an attribute class defines a valid sequence of positional parameters for that class. Named parameters are defined by the non-static, public, and read-write fields or properties of the attribute class.
The three properties of AttributeUsageAttribute are set by defining the following parameters:
This positional parameter specifies the program elements that the indicated attribute can be placed on. The set of all possible elements that you can place an attribute on is listed in the AttributeTargets enumeration. You can combine several AttributeTargets values using a bitwise OR operation to get the desired combination of valid program elements.
This named parameter specifies whether the indicated attribute can be specified more than once for a given program element.
This named parameter specifies whether the indicated attribute can be inherited by derived classes and overriding members.
For more information about using attributes, see Attribute and Extending Metadata Using Attributes.
.NET Framework
Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0.NET Framework Client Profile
Supported in: 4, 3.5 SP1Portable Class Library
Supported in: Portable Class LibraryWindows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.