Thread.GetData(LocalDataStoreSlot) Método

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

public static object GetData(LocalDataStoreSlot slot);

static member GetData : LocalDataStoreSlot -> obj

Public Shared Function GetData (slot As LocalDataStoreSlot) As Object

Parâmetros

Retornos

O valor recuperado.

Exemplos

Esta seção contém dois exemplos de código. O primeiro exemplo mostra como usar um campo marcado com o ThreadStaticAttribute atributo para armazenar informações específicas do thread. O segundo exemplo mostra como usar um slot de dados para fazer a mesma coisa.

Primeiro exemplo

O exemplo a seguir mostra como usar um campo marcado para ThreadStaticAttribute conter informações específicas do thread. Essa técnica fornece melhor desempenho do que a técnica mostrada no segundo exemplo.

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
 */

open System
open System.Threading

type ThreadData() =
    // Create a static variable to hold the data for each thread.
    [<ThreadStatic; DefaultValue>]
    static val mutable private threadSpecificData : int

    static member ThreadStaticDemo() =
        // Store the managed thread id for each thread in the static
        // variable.
        ThreadData.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.
        printfn $"Data for managed thread {Thread.CurrentThread.ManagedThreadId}: {ThreadData.threadSpecificData}" 

for i = 0 to 2 do 
    let newThread = Thread 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

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

Segundo exemplo

O exemplo a seguir demonstra como usar um slot de dados para armazenar informações específicas do thread.

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());
    }
}

open System
open System.Threading

module Slot =
    let randomGenerator = Random()
    let localSlot = Thread.AllocateDataSlot()


    let 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.
        printfn $"Data in thread_{AppDomain.GetCurrentThreadId()}'s data slot: {Thread.GetData localSlot, 3}"

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

        printfn $"Data in thread_{AppDomain.GetCurrentThreadId()}'s data slot: {Thread.GetData localSlot, 3}"

let newThreads =
    [| for _ = 0 to 3 do
           let thread = Thread Slot.slotTest
           thread.Start()
           thread |]

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

Comentários

Os threads usam um mecanismo de memória do repositório local para armazenar dados específicos do thread. O common language runtime aloca uma matriz de armazenamento de dados de vários slots para cada processo quando ele é criado. O thread pode alocar um slot de dados no armazenamento de dados, armazenar e recuperar um valor de dados no slot e liberar o slot para reutilização após a expiração do thread. Os slots de dados são exclusivos por thread. Nenhum outro thread (nem mesmo um thread filho) pode obter esses dados.

Confira também

• SetData(LocalDataStoreSlot, Object)
• Threads e threading
• Armazenamento local de thread: Campos estáticos relativos a thread e slots de dados