ThreadLocal<T> 類別

定義

提供資料的執行緒區域儲存區。Provides thread-local storage of data.

generic <typename T>
public ref class ThreadLocal : IDisposable
public class ThreadLocal<T> : IDisposable
type ThreadLocal<'T> = class
    interface IDisposable
Public Class ThreadLocal(Of T)
Implements IDisposable

類型參數

T

指定每個執行緒儲存的資料型別。Specifies the type of data stored per-thread.

繼承
ThreadLocal<T>
實作

範例

下列範例顯示如何使用 ThreadLocal<T>The following example shows how to use ThreadLocal<T>:

using System;
using System.Threading;
using System.Threading.Tasks;

class ThreadLocalDemo
{
    
        // Demonstrates:
        //      ThreadLocal(T) constructor
        //      ThreadLocal(T).Value
        //      One usage of ThreadLocal(T)
        static void Main()
        {
            // Thread-Local variable that yields a name for a thread
            ThreadLocal<string> ThreadName = new ThreadLocal<string>(() =>
            {
                return "Thread" + Thread.CurrentThread.ManagedThreadId;
            });

            // Action that prints out ThreadName for the current thread
            Action action = () =>
            {
                // If ThreadName.IsValueCreated is true, it means that we are not the
                // first action to run on this thread.
                bool repeat = ThreadName.IsValueCreated;

                Console.WriteLine("ThreadName = {0} {1}", ThreadName.Value, repeat ? "(repeat)" : "");
            };

            // Launch eight of them.  On 4 cores or less, you should see some repeat ThreadNames
            Parallel.Invoke(action, action, action, action, action, action, action, action);

            // Dispose when you are done
            ThreadName.Dispose();
        }
}
// This multithreading example can produce different outputs for each 'action' invocation and will vary with each run.
// Therefore, the example output will resemble but may not exactly match the following output (from a 4 core processor):
// ThreadName = Thread5 
// ThreadName = Thread6 
// ThreadName = Thread4 
// ThreadName = Thread6 (repeat)
// ThreadName = Thread1 
// ThreadName = Thread4 (repeat)
// ThreadName = Thread7 
// ThreadName = Thread5 (repeat)
Imports System.Threading
Imports System.Threading.Tasks

Module ThreadLocalDemo

    ' Demonstrates:
    ' ThreadLocal(T) constructor
    ' ThreadLocal(T).Value
    ' One usage of ThreadLocal(T)
    Sub Main()
        ' Thread-Local variable that yields a name for a thread
        Dim ThreadName As New ThreadLocal(Of String)(
            Function()
                Return "Thread" & Thread.CurrentThread.ManagedThreadId
            End Function)

        ' Action that prints out ThreadName for the current thread
        Dim action As Action =
            Sub()
                ' If ThreadName.IsValueCreated is true, it means that we are not the
                ' first action to run on this thread.
                Dim repeat As Boolean = ThreadName.IsValueCreated

                Console.WriteLine("ThreadName = {0} {1}", ThreadName.Value, If(repeat, "(repeat)", ""))
            End Sub

        ' Launch eight of them. On 4 cores or less, you should see some repeat ThreadNames
        Parallel.Invoke(action, action, action, action, action, action, action, action)

        ' Dispose when you are done
        ThreadName.Dispose()
    End Sub
End Module
' This multithreading example can produce different outputs for each 'action' invocation and will vary with each run.
' Therefore, the example output will resemble but may not exactly match the following output (from a 4 core processor):
' ThreadName = Thread5 
' ThreadName = Thread6 
' ThreadName = Thread4 
' ThreadName = Thread6 (repeat)
' ThreadName = Thread1 
' ThreadName = Thread4 (repeat)
' ThreadName = Thread7 
' ThreadName = Thread5 (repeat)    

建構函式

ThreadLocal<T>()

初始化 ThreadLocal<T> 執行個體。Initializes the ThreadLocal<T> instance.

ThreadLocal<T>(Boolean)

初始化 ThreadLocal<T> 執行個體,並指定是否可從任何執行緒存取所有值。Initializes the ThreadLocal<T> instance and specifies whether all values are accessible from any thread.

ThreadLocal<T>(Func<T>)

使用指定的 valueFactory 函式來初始化 ThreadLocal<T> 的執行個體。Initializes the ThreadLocal<T> instance with the specified valueFactory function.

ThreadLocal<T>(Func<T>, Boolean)

使用指定的 valueFactory 函式及指出是否可從任何執行緒存取所有值的旗標,初始化 ThreadLocal<T> 執行個體。Initializes the ThreadLocal<T> instance with the specified valueFactory function and a flag that indicates whether all values are accessible from any thread.

屬性

IsValueCreated

取得值,這個值表示 Value 是否已在目前執行緒中完成初始化。Gets whether Value is initialized on the current thread.

Value

取得或設定目前執行緒的這個執行個體的值。Gets or sets the value of this instance for the current thread.

Values

取得清單,其中包含已存取這個執行個體的所有執行緒目前所儲存的所有值。Gets a list for all of the values currently stored by all of the threads that have accessed this instance.

方法

Dispose()

釋放 ThreadLocal<T> 類別目前的執行個體所使用的全部資源。Releases all resources used by the current instance of the ThreadLocal<T> class.

Dispose(Boolean)

釋放這個 ThreadLocal<T> 執行個體所使用的資源。Releases the resources used by this ThreadLocal<T> instance.

Equals(Object)

判斷指定的物件是否等於目前的物件。Determines whether the specified object is equal to the current object.

(繼承來源 Object)
Finalize()

釋放這個 ThreadLocal<T> 執行個體所使用的資源。Releases the resources used by this ThreadLocal<T> instance.

GetHashCode()

作為預設雜湊函數。Serves as the default hash function.

(繼承來源 Object)
GetType()

取得目前執行個體的 TypeGets the Type of the current instance.

(繼承來源 Object)
MemberwiseClone()

建立目前 Object 的淺層複製。Creates a shallow copy of the current Object.

(繼承來源 Object)
ToString()

建立並傳回目前執行緒的這個執行個體的字串表示。Creates and returns a string representation of this instance for the current thread.

適用於

執行緒安全性

除了 Dispose() 以外,ThreadLocal<T> 的所有 public 和 protected 成員都是安全線程,而且可以從多個執行緒同時使用。With the exception of Dispose(), all public and protected members of ThreadLocal<T> are thread-safe and may be used concurrently from multiple threads. Value 和 @no__t 1 屬性傳回的值,對於存取屬性的執行緒而言是特定的。The value returned for the Value and IsValueCreated properties is specific for the thread on which the property is accessed.

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