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başlangıç zamanında iş parçacığı oluşturma ve veri geçirme

bir işletim sistemi işlemi oluşturulduğunda, işletim sistemi herhangi bir özgün uygulama etki alanı dahil olmak üzere bu işlemdeki kodu yürütmek için bir iş parçacığı ekler. Bu noktadan itibaren, uygulama etki alanları mutlaka herhangi bir işletim sistemi iş parçacığı oluşturulmadan veya yok edilmeden oluşturulabilir ve yok edilebilir. Yürütülen kod yönetilen kodsa, geçerli uygulama etki alanında çalışan iş parçacığı için Threadtüründeki statik CurrentThread özelliği alınarak bir Thread nesnesi elde edilebilir. Bu konu başlığında iş parçacığı oluşturma işlemi açıklanır ve iş parçacığı yordamına veri geçirmenin alternatifleri açıklanır.

Thread oluşturma

Yeni bir Thread nesnesi oluşturmak, yeni bir yönetilen iş parçacığı oluşturur. Thread sınıfı, ThreadStart temsilcisi veya ParameterizedThreadStart temsilcisi alan oluşturuculara sahiptir; temsilci, Start yöntemini çağırdığınızda yeni iş parçacığı tarafından çağrılan yöntemi sarmalar. Start birden çok kez çağrılması, bir ThreadStateException oluşmasına sebep olur.

Start yöntemi, genellikle yeni iş parçacığı gerçekten başlamadan önce hemen geri döner. herhangi bir anda iş parçacığının durumunu belirlemek için ThreadState ve IsAlive özelliklerini kullanabilirsiniz, ancak bu özellikler hiçbir zaman iş parçacıklarının etkinliklerini eşitlemek için kullanılmamalıdır.

Uyarı

Bir iş parçacığı başlatıldıktan sonra, Thread nesnesine başvurunun tutulması gerekmez. İş parçacığı yordamı bitene kadar iş parçacığı yürütülmeye devam eder.

Aşağıdaki kod örneği, başka bir nesnedeki örneği ve statik yöntemleri çağırmak için iki yeni iş parçacığı oluşturur.

using System;
using System.Threading;

public class ServerClass
{
    // The method that will be called when the thread is started.
    public void InstanceMethod()
    {
        Console.WriteLine(
            "ServerClass.InstanceMethod is running on another thread.");

        // Pause for a moment to provide a delay to make
        // threads more apparent.
        Thread.Sleep(3000);
        Console.WriteLine(
            "The instance method called by the worker thread has ended.");
    }

    public static void StaticMethod()
    {
        Console.WriteLine(
            "ServerClass.StaticMethod is running on another thread.");

        // Pause for a moment to provide a delay to make
        // threads more apparent.
        Thread.Sleep(5000);
        Console.WriteLine(
            "The static method called by the worker thread has ended.");
    }
}

public class Simple
{
    public static void Main()
    {
        ServerClass serverObject = new ServerClass();

        // Create the thread object, passing in the
        // serverObject.InstanceMethod method using a
        // ThreadStart delegate.
        Thread InstanceCaller = new(new ThreadStart(serverObject.InstanceMethod));

        // Start the thread.
        InstanceCaller.Start();

        Console.WriteLine("The Main() thread calls this after "
            + "starting the new InstanceCaller thread.");

        // Create the thread object, passing in the
        // ServerClass.StaticMethod method using a
        // ThreadStart delegate.
        Thread StaticCaller = new(new ThreadStart(ServerClass.StaticMethod));

        // Start the thread.
        StaticCaller.Start();

        Console.WriteLine("The Main() thread calls this after "
            + "starting the new StaticCaller thread.");
    }
}
// The example displays the output like the following:
//    The Main() thread calls this after starting the new InstanceCaller thread.
//    The Main() thread calls this after starting the new StaticCaller thread.
//    ServerClass.StaticMethod is running on another thread.
//    ServerClass.InstanceMethod is running on another thread.
//    The instance method called by the worker thread has ended.
//    The static method called by the worker thread has ended.

Imports System.Threading

Public class ServerClass
    ' The method that will be called when the thread is started.
    Public Sub InstanceMethod()
        Console.WriteLine(
            "ServerClass.InstanceMethod is running on another thread.")

        ' Pause for a moment to provide a delay to make
        ' threads more apparent.
        Thread.Sleep(3000)
        Console.WriteLine(
            "The instance method called by the worker thread has ended.")
    End Sub

    Public Shared Sub SharedMethod()
        Console.WriteLine(
            "ServerClass.SharedMethod is running on another thread.")

        ' Pause for a moment to provide a delay to make
        ' threads more apparent.
        Thread.Sleep(5000)
        Console.WriteLine(
            "The Shared method called by the worker thread has ended.")
    End Sub
End Class

Public class Simple
    Public Shared Sub Main()
        Dim serverObject As New ServerClass()

        ' Create the thread object, passing in the
        ' serverObject.InstanceMethod method using a
        ' ThreadStart delegate.
        Dim InstanceCaller As New Thread(AddressOf serverObject.InstanceMethod)

        ' Start the thread.
        InstanceCaller.Start()

        Console.WriteLine("The Main() thread calls this after " _
            + "starting the new InstanceCaller thread.")

        ' Create the thread object, passing in the
        ' ServerClass.SharedMethod method using a
        ' ThreadStart delegate.
        Dim SharedCaller As New Thread( _
            New ThreadStart(AddressOf ServerClass.SharedMethod))

        ' Start the thread.
        SharedCaller.Start()

        Console.WriteLine("The Main() thread calls this after " _
            + "starting the new SharedCaller thread.")
    End Sub
End Class
' The example displays output like the following:
'    The Main() thread calls this after starting the new InstanceCaller thread.
'    The Main() thread calls this after starting the new SharedCaller thread.
'    ServerClass.SharedMethod is running on another thread.
'    ServerClass.InstanceMethod is running on another thread.
'    The instance method called by the worker thread has ended.
'    The shared method called by the worker thread has ended.

İş parçacıklarına veri geçirme

ParameterizedThreadStart temsilcisi, Thread.Start(Object)çağırdığınızda veri içeren bir nesneyi iş parçacığına geçirmek için kolay bir yol sağlar. Kod örneği için bkz. ParameterizedThreadStart.

ParameterizedThreadStart yöntemi herhangi bir nesneyi kabul ettiğinden, Thread.Start(Object) temsilcisinin kullanılması veri geçirmenin tür açısından güvenli bir yolu değildir. Alternatif olarak, iş parçacığı yordamını ve bir yardımcı sınıftaki verileri kapsüllemek ve iş parçacığı yordamını yürütmek için ThreadStart temsilcisini kullanmaktır. Aşağıdaki örnekte bu teknik gösterilmektedir:

using System;
using System.Threading;

// The ThreadWithState class contains the information needed for
// a task, and the method that executes the task.
//
public class ThreadWithState
{
    // State information used in the task.
    private string _boilerplate;
    private int _numberValue;

    // The constructor obtains the state information.
    public ThreadWithState(string text, int number)
    {
        _boilerplate = text;
        _numberValue = number;
    }

    // The thread procedure performs the task, such as formatting
    // and printing a document.
    public void ThreadProc()
    {
        Console.WriteLine(_boilerplate, _numberValue);
    }
}

// Entry point for the example.
public class Example
{
    public static void Main()
    {
        // Supply the state information required by the task.
        ThreadWithState tws = new("This report displays the number {0}.", 42);

        // Create a thread to execute the task, and then
        // start the thread.
        Thread t = new(new ThreadStart(tws.ThreadProc));
        t.Start();
        Console.WriteLine("Main thread does some work, then waits.");
        t.Join();
        Console.WriteLine(
            "Independent task has completed; main thread ends.");
    }
}

// The example displays the following output:
//       Main thread does some work, then waits.
//       This report displays the number 42.
//       Independent task has completed; main thread ends.

Imports System.Threading

' The ThreadWithState class contains the information needed for
' a task, and the method that executes the task.
Public Class ThreadWithState
    ' State information used in the task.
    Private boilerplate As String
    Private numberValue As Integer

    ' The constructor obtains the state information.
    Public Sub New(text As String, number As Integer)
        boilerplate = text
        numberValue = number
    End Sub

    ' The thread procedure performs the task, such as formatting
    ' and printing a document.
    Public Sub ThreadProc()
        Console.WriteLine(boilerplate, numberValue)
    End Sub
End Class

' Entry point for the example.
'
Public Class Example
    Public Shared Sub Main()
        ' Supply the state information required by the task.
        Dim tws As New ThreadWithState( _
            "This report displays the number {0}.", 42)

        ' Create a thread to execute the task, and then
        ' start the thread.
        Dim t As New Thread(New ThreadStart(AddressOf tws.ThreadProc))
        t.Start()
        Console.WriteLine("Main thread does some work, then waits.")
        t.Join()
        Console.WriteLine( _
            "Independent task has completed main thread ends.")
    End Sub
End Class
' The example displays the following output:
'       Main thread does some work, then waits.
'       This report displays the number 42.
'       Independent task has completed; main thread ends.

Ne ThreadStart ne de ParameterizedThreadStart temsilcisi bir dönüş değeri döndürmez, çünkü eşzamansız bir çağrıdan veri döndürülecek bir yer yoktur. Bir iş parçacığı yönteminin sonuçlarını almak için, sonraki bölümde gösterildiği gibi bir geri çağırma yöntemi kullanabilirsiniz.

Geri çağırma yöntemleriyle iş parçacıklarından veri alma

Aşağıdaki örnek, bir iş parçacığından veri çağıran bir geri çağırma yöntemini gösterir. Verileri içeren sınıfın oluşturucu ve iş parçacığı yöntemi de geri çağırma yöntemini temsil eden bir temsilci kabul eder; iş parçacığı yöntemi bitmeden önce geri çağırma temsilcisini çağırır.

using System;
using System.Threading;

// The ThreadWithState2 class contains the information needed for
// a task, the method that executes the task, and a delegate
// to call when the task is complete.
public class ThreadWithState2
{
    // State information used in the task.
    private string _boilerplate;
    private int _numberValue;

    // Delegate used to execute the callback method when the
    // task is complete.
    private ExampleCallback _callback;

    // The constructor obtains the state information and the
    // callback delegate.
    public ThreadWithState2(string text, int number,
        ExampleCallback callbackDelegate)
    {
        _boilerplate = text;
        _numberValue = number;
        _callback = callbackDelegate;
    }

    // The thread procedure performs the task, such as
    // formatting and printing a document, and then invokes
    // the callback delegate with the number of lines printed.
    public void ThreadProc()
    {
        Console.WriteLine(_boilerplate, _numberValue);
        _callback?.Invoke(1);
    }
}

// Delegate that defines the signature for the callback method.
public delegate void ExampleCallback(int lineCount);

// Entry point for the example.
public class Example2
{
    public static void Main()
    {
        // Supply the state information required by the task.
        ThreadWithState2 tws = new(
            "This report displays the number {0}.",
            42,
            new ExampleCallback(ResultCallback)
        );

        Thread t = new(new ThreadStart(tws.ThreadProc));
        t.Start();
        Console.WriteLine("Main thread does some work, then waits.");
        t.Join();
        Console.WriteLine(
            "Independent task has completed; main thread ends.");
    }

    // The callback method must match the signature of the
    // callback delegate.
    public static void ResultCallback(int lineCount)
    {
        Console.WriteLine($"Independent task printed {lineCount} lines.");
    }
}

// The example displays the following output:
//       Main thread does some work, then waits.
//       This report displays the number 42.
//       Independent task printed 1 lines.
//       Independent task has completed; main thread ends.

Imports System.Threading

' The ThreadWithState2 class contains the information needed for
' a task, the method that executes the task, and a delegate
' to call when the task is complete.
Public Class ThreadWithState2
    ' State information used in the task.
    Private boilerplate As String
    Private numberValue As Integer

    ' Delegate used to execute the callback method when the
    ' task is complete.
    Private callback As ExampleCallback

    ' The constructor obtains the state information and the
    ' callback delegate.
    Public Sub New(text As String, number As Integer, _
        callbackDelegate As ExampleCallback)
        boilerplate = text
        numberValue = number
        callback = callbackDelegate
    End Sub

    ' The thread procedure performs the task, such as
    ' formatting and printing a document, and then invokes
    ' the callback delegate with the number of lines printed.
    Public Sub ThreadProc()
        Console.WriteLine(boilerplate, numberValue)
        If Not (callback Is Nothing) Then
            callback(1)
        End If
    End Sub
End Class

' Delegate that defines the signature for the callback method.
Public Delegate Sub ExampleCallback(lineCount As Integer)

Public Class Example2
    Public Shared Sub Main()
        ' Supply the state information required by the task.
        Dim tws As New ThreadWithState2( _
            "This report displays the number {0}.", _
            42, _
            AddressOf ResultCallback)

        Dim t As New Thread(AddressOf tws.ThreadProc)
        t.Start()
        Console.WriteLine("Main thread does some work, then waits.")
        t.Join()
        Console.WriteLine( _
            "Independent task has completed; main thread ends.")
    End Sub

    Public Shared Sub ResultCallback(lineCount As Integer)
        Console.WriteLine( _
            "Independent task printed {0} lines.", lineCount)
    End Sub
End Class
' The example displays the following output:
'       Main thread does some work, then waits.
'       This report displays the number 42.
'       Independent task printed 1 lines.
'       Independent task has completed; main thread ends.

Ayrıca bkz.

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