Thread.GetData(LocalDataStoreSlot) 方法

參考

定義

命名空間:: System.Threading

組件:: System.Threading.Thread.dll

組件:: netstandard.dll

組件:: mscorlib.dll

重要

部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。

從目前執行緒上、目前執行緒之目前定義域中的指定位置擷取數值。為獲得較佳的效能，請改用以 ThreadStaticAttribute 屬性標示的欄位。

public:
 static System::Object ^ GetData(LocalDataStoreSlot ^ slot);

public static object? GetData (LocalDataStoreSlot slot);

public static object GetData (LocalDataStoreSlot slot);

static member GetData : LocalDataStoreSlot -> obj

Public Shared Function GetData (slot As LocalDataStoreSlot) As Object

參數

slot: LocalDataStoreSlot

要從其中取得值的 LocalDataStoreSlot。

傳回

Object

擷取的數值。

範例

本節包含兩個程式碼範例。第一個範例示範如何使用標記有屬性的欄位 ThreadStaticAttribute 來保存執行緒特定的資訊。第二個範例顯示如何使用資料位置來執行相同的動作。

第一個範例

下列範例示範如何使用標記為的欄位 ThreadStaticAttribute 來保存執行緒特定的資訊。這項技術提供的效能比第二個範例中所示的技巧更好。

using namespace System;
using namespace System::Threading;

ref class ThreadData
{
private:
   [ThreadStatic]
   static int threadSpecificData;

public:
   static void ThreadStaticDemo()
   {
      // Store the managed thread id for each thread in the static
      // variable.
      threadSpecificData = Thread::CurrentThread->ManagedThreadId;
      
      // Allow other threads time to execute the same code, to show
      // that the static data is unique to each thread.
      Thread::Sleep( 1000 );

      // Display the static data.
      Console::WriteLine( "Data for managed thread {0}: {1}", 
         Thread::CurrentThread->ManagedThreadId, threadSpecificData );
   }
};

int main()
{
   for ( int i = 0; i < 3; i++ )
   {
      Thread^ newThread = 
          gcnew Thread( gcnew ThreadStart( ThreadData::ThreadStaticDemo )); 
      newThread->Start();
   }
}

/* This code example produces output similar to the following:

Data for managed thread 4: 4
Data for managed thread 5: 5
Data for managed thread 3: 3
 */

using System;
using System.Threading;

class Test
{
    static void Main()
    {
        for(int i = 0; i < 3; i++)
        {
            Thread newThread = new Thread(ThreadData.ThreadStaticDemo);
            newThread.Start();
        }
    }
}

class ThreadData
{
    [ThreadStatic]
    static int threadSpecificData;

    public static void ThreadStaticDemo()
    {
        // Store the managed thread id for each thread in the static
        // variable.
        threadSpecificData = Thread.CurrentThread.ManagedThreadId;
      
        // Allow other threads time to execute the same code, to show
        // that the static data is unique to each thread.
        Thread.Sleep( 1000 );

        // Display the static data.
        Console.WriteLine( "Data for managed thread {0}: {1}", 
            Thread.CurrentThread.ManagedThreadId, threadSpecificData );
    }
}

/* This code example produces output similar to the following:

Data for managed thread 4: 4
Data for managed thread 5: 5
Data for managed thread 3: 3
 */

Imports System.Threading

Class Test

    <MTAThread> _
    Shared Sub Main()

        For i As Integer = 1 To 3
            Dim newThread As New Thread(AddressOf ThreadData.ThreadStaticDemo)
            newThread.Start()
        Next i

    End Sub

End Class

Class ThreadData

    <ThreadStatic> _
    Shared threadSpecificData As Integer

    Shared Sub ThreadStaticDemo()

        ' Store the managed thread id for each thread in the static
        ' variable.
        threadSpecificData = Thread.CurrentThread.ManagedThreadId
      
        ' Allow other threads time to execute the same code, to show
        ' that the static data is unique to each thread.
        Thread.Sleep( 1000 )

        ' Display the static data.
        Console.WriteLine( "Data for managed thread {0}: {1}", _
            Thread.CurrentThread.ManagedThreadId, threadSpecificData )

    End Sub

End Class

' This code example produces output similar to the following:
'
'Data for managed thread 4: 4
'Data for managed thread 5: 5
'Data for managed thread 3: 3

第二個範例

下列範例示範如何使用資料位置來儲存執行緒特定的資訊。

using namespace System;
using namespace System::Threading;
ref class Slot
{
private:
   static Random^ randomGenerator;
   static LocalDataStoreSlot^ localSlot;
   static Slot()
   {
      randomGenerator = gcnew Random;
      localSlot = Thread::AllocateDataSlot();
   }


public:
   static void SlotTest()
   {
      
      // Set different data in each thread's data slot.
      Thread::SetData( localSlot, randomGenerator->Next( 1, 200 ) );
      
      // Write the data from each thread's data slot.
      Console::WriteLine( "Data in thread_{0}'s data slot: {1,3}", AppDomain::GetCurrentThreadId().ToString(), Thread::GetData( localSlot )->ToString() );
      
      // Allow other threads time to execute SetData to show
      // that a thread's data slot is unique to the thread.
      Thread::Sleep( 1000 );
      Console::WriteLine( "Data in thread_{0}'s data slot: {1,3}", AppDomain::GetCurrentThreadId().ToString(), Thread::GetData( localSlot )->ToString() );
   }

};

int main()
{
   array<Thread^>^newThreads = gcnew array<Thread^>(4);
   for ( int i = 0; i < newThreads->Length; i++ )
   {
      newThreads[ i ] = gcnew Thread( gcnew ThreadStart( &Slot::SlotTest ) );
      newThreads[ i ]->Start();

   }
}

using System;
using System.Threading;

class Test
{
    static void Main()
    {
        Thread[] newThreads = new Thread[4];
        for(int i = 0; i < newThreads.Length; i++)
        {
            newThreads[i] = new Thread(
                new ThreadStart(Slot.SlotTest));
            newThreads[i].Start();
        }
    }
}

class Slot
{
    static Random randomGenerator;
    static LocalDataStoreSlot localSlot;

    static Slot()
    {
        randomGenerator = new Random();
        localSlot = Thread.AllocateDataSlot();
    }

    public static void SlotTest()
    {
        // Set different data in each thread's data slot.
        Thread.SetData(localSlot, randomGenerator.Next(1, 200));

        // Write the data from each thread's data slot.
        Console.WriteLine("Data in thread_{0}'s data slot: {1,3}", 
            AppDomain.GetCurrentThreadId().ToString(),
            Thread.GetData(localSlot).ToString());

        // Allow other threads time to execute SetData to show
        // that a thread's data slot is unique to the thread.
        Thread.Sleep(1000);

        Console.WriteLine("Data in thread_{0}'s data slot: {1,3}", 
            AppDomain.GetCurrentThreadId().ToString(),
            Thread.GetData(localSlot).ToString());
    }
}

Imports System.Threading

Class Test

    <MTAThread> _
    Shared Sub Main()
        Dim newThreads(3) As Thread
        For i As Integer = 0 To newThreads.Length - 1
            newThreads(i) = New Thread(AddressOf Slot.SlotTest)
            newThreads(i).Start()
        Next i
    End Sub

End Class

Public Class Slot

    Shared randomGenerator As Random
    Shared localSlot As LocalDataStoreSlot

    Shared Sub New()
        randomGenerator = new Random()
        localSlot = Thread.AllocateDataSlot()
    End Sub

    Shared Sub SlotTest()

        ' Set different data in each thread's data slot.
        Thread.SetData(localSlot, randomGenerator.Next(1, 200))

        ' Write the data from each thread's data slot.
        Console.WriteLine("Data in thread_{0}'s data slot: {1,3}", _
            AppDomain.GetCurrentThreadId().ToString(), _
            Thread.GetData(localSlot).ToString())

        ' Allow other threads time to execute SetData to show
        ' that a thread's data slot is unique to the thread.
        Thread.Sleep(1000)

        ' Write the data from each thread's data slot.
        Console.WriteLine("Data in thread_{0}'s data slot: {1,3}", _
            AppDomain.GetCurrentThreadId().ToString(), _
            Thread.GetData(localSlot).ToString())
    End Sub

End Class

備註

重要

.NET Framework 提供兩種機制，可讓您使用執行緒區域儲存區 (TLS) ：執行緒相關的靜態欄位 (也就是說，以 ThreadStaticAttribute 屬性) 和資料位置標記的欄位。執行緒相關的靜態欄位提供比資料插槽更好的效能，並啟用編譯時間類型檢查。如需使用 TLS 的詳細資訊，請參閱執行緒區域儲存體： Thread-Relative 靜態欄位和資料槽。

執行緒使用本機存放區記憶體機制來儲存執行緒特定資料。 Common language runtime 會在每個進程建立時，將多個位置的資料存放區陣列配置給每個進程。執行緒可以配置資料存放區中的資料位置、儲存並取出位置中的資料值，以及釋放位置以線上程到期之後重複使用。每個執行緒的資料插槽都是唯一的。沒有其他執行緒 (甚至是子執行緒) 可以取得該資料。

注意

GetData 是 Shared 一律套用至目前執行中線程的方法，即使您使用參考另一個執行緒的變數來呼叫它也是一樣。若要避免混淆，請在呼叫方法時使用類別名稱 Shared ： Dim test As Object = Thread.GetData(testSlot) 。

適用於

共用方式為

Thread.GetData(LocalDataStoreSlot) 方法

定義

參數

傳回

範例

備註

適用於

另請參閱

其他資源