ThreadStaticAttribute Class (System)

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.NET Framework Class Library
ThreadStaticAttribute Class

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Indicates that the value of a static field is unique for each thread.

Inheritance Hierarchy
System.Object
  System.Attribute
    System.ThreadStaticAttribute

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)
Syntax
Visual Basic

<SerializableAttribute> _
<ComVisibleAttribute(True)> _
<AttributeUsageAttribute(AttributeTargets.Field, Inherited := False)> _
Public Class ThreadStaticAttribute _
	Inherits Attribute
C#

[SerializableAttribute]
[ComVisibleAttribute(true)]
[AttributeUsageAttribute(AttributeTargets.Field, Inherited = false)]
public class ThreadStaticAttribute : Attribute
Visual C++

[SerializableAttribute]
[ComVisibleAttribute(true)]
[AttributeUsageAttribute(AttributeTargets::Field, Inherited = false)]
public ref class ThreadStaticAttribute : public Attribute
F#

[<SerializableAttribute>]
[<ComVisibleAttribute(true)>]
[<AttributeUsageAttribute(AttributeTargets.Field, Inherited = false)>]
type ThreadStaticAttribute =  
    class
        inherit Attribute
    end

The ThreadStaticAttribute type exposes the following members.

Constructors
  Name Description
Public method Supported by Portable Class Library ThreadStaticAttribute Initializes a new instance of the ThreadStaticAttribute class.
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Properties
  Name Description
Public property TypeId When implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute.)
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Methods
  Name Description
Public method Supported by Portable Class Library Equals Infrastructure. Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute.)
Protected method Supported by Portable Class Library Finalize Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public method Supported by Portable Class Library GetHashCode Returns the hash code for this instance. (Inherited from Attribute.)
Public method Supported by Portable Class Library GetType Gets the Type of the current instance. (Inherited from Object.)
Public method 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.)
Public method Match When overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.)
Protected method Supported by Portable Class Library MemberwiseClone Creates a shallow copy of the current Object. (Inherited from Object.)
Public method Supported by Portable Class Library ToString Returns a string that represents the current object. (Inherited from Object.)
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Explicit Interface Implementations
  Name Description
Explicit interface implemetation Private method _Attribute.GetIDsOfNames Maps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.)
Explicit interface implemetation Private method _Attribute.GetTypeInfo Retrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.)
Explicit interface implemetation Private method _Attribute.GetTypeInfoCount Retrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.)
Explicit interface implemetation Private method _Attribute.Invoke Provides access to properties and methods exposed by an object. (Inherited from Attribute.)
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Remarks

A static field marked with ThreadStaticAttribute is not shared between threads. Each executing thread has a separate instance of the field, and independently sets and gets values for that field. If the field is accessed on a different thread, it will contain a different value.

Note Note

Do not specify initial values for fields marked with ThreadStaticAttribute, because such initialization occurs only once, when the class constructor executes, and therefore affects only one thread. If you do not specify an initial value, you can rely on the field being initialized to its default value if it is a value type, or to null if it is a reference type.

Use this attribute as it is, and do not derive from it. The following is an example of ThreadStaticAttribute syntax:

C#
[ThreadStatic]
static int value;
Visual Basic
<ThreadStatic> _
Shared value As Integer

For more information about using attributes, see Extending Metadata Using Attributes.

Version Information

.NET Framework

Supported in: 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library
Platforms

Windows 8 Release Preview, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 SP2, Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Thread Safety
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
See Also

Reference

System Namespace
Attribute
Thread

Other Resources

Extending Metadata Using Attributes
Managed Threading