Thread.Join 方法

参考

定义

命名空间:: System.Threading

程序集:: netstandard.dll, System.Threading.Thread.dll

程序集:: System.Threading.Thread.dll

程序集:: mscorlib.dll

程序集:: netstandard.dll

重要

一些信息与预发行产品相关，相应产品在发行之前可能会进行重大修改。对于此处提供的信息，Microsoft 不作任何明示或暗示的担保。

在此实例表示的线程终止前，阻止调用线程。

重载

Join()	在继续执行标准的 COM 和 `SendMessage` 消息泵处理期间，阻止调用线程，直到由该实例表示的线程终止。
Join(Int32)	在继续执行标准的 COM 和 SendMessage 消息泵处理期间，阻止调用线程，直到由该实例表示的线程终止或经过了指定时间为止。
Join(TimeSpan)	在继续执行标准的 COM 和 SendMessage 消息泵处理期间，阻止调用线程，直到由该实例表示的线程终止或经过了指定时间为止。

Join()

Source:: Thread.cs

Source:: Thread.cs

Source:: Thread.cs

在继续执行标准的 COM 和 SendMessage 消息泵处理期间，阻止调用线程，直到由该实例表示的线程终止。

public:
 void Join();

public void Join();

member this.Join : unit -> unit

Public Sub Join ()

例外

ThreadStateException

调用方尝试加入处于 Unstarted 状态的线程。

ThreadInterruptedException

线程在等待时中断。

注解

Join 是一种同步方法，它阻止调用线程 (即调用方法的线程) ，直到调用其方法的 Join 线程完成。使用此方法可确保线程已终止。如果线程未终止，调用方将无限期阻止。在以下示例中 Thread1 ，线程调用 Join() 的 Thread2方法，这会导致 Thread1 在完成之前 Thread2 阻止。

using System;
using System.Threading;

public class Example
{
   static Thread thread1, thread2;
   
   public static void Main()
   {
      thread1 = new Thread(ThreadProc);
      thread1.Name = "Thread1";
      thread1.Start();
      
      thread2 = new Thread(ThreadProc);
      thread2.Name = "Thread2";
      thread2.Start();   
   }

   private static void ThreadProc()
   {
      Console.WriteLine("\nCurrent thread: {0}", Thread.CurrentThread.Name);
      if (Thread.CurrentThread.Name == "Thread1" && 
          thread2.ThreadState != ThreadState.Unstarted)
         thread2.Join();
      
      Thread.Sleep(4000);
      Console.WriteLine("\nCurrent thread: {0}", Thread.CurrentThread.Name);
      Console.WriteLine("Thread1: {0}", thread1.ThreadState);
      Console.WriteLine("Thread2: {0}\n", thread2.ThreadState);
   }
}
// The example displays output like the following:
//       Current thread: Thread1
//       
//       Current thread: Thread2
//       
//       Current thread: Thread2
//       Thread1: WaitSleepJoin
//       Thread2: Running
//       
//       
//       Current thread: Thread1
//       Thread1: Running
//       Thread2: Stopped

open System.Threading

let mutable thread1, thread2 =
    Unchecked.defaultof<Thread>, Unchecked.defaultof<Thread>

let threadProc () =
    printfn $"\nCurrent thread: {Thread.CurrentThread.Name}"

    if
        Thread.CurrentThread.Name = "Thread1"
        && thread2.ThreadState <> ThreadState.Unstarted
    then
        thread2.Join()

    Thread.Sleep 4000
    printfn $"\nCurrent thread: {Thread.CurrentThread.Name}"
    printfn $"Thread1: {thread1.ThreadState}"
    printfn $"Thread2: {thread2.ThreadState}\n"

thread1 <- Thread threadProc
thread1.Name <- "Thread1"
thread1.Start()

thread2 <- Thread threadProc
thread2.Name <- "Thread2"
thread2.Start()

// The example displays output like the following:
//       Current thread: Thread1
//
//       Current thread: Thread2
//
//       Current thread: Thread2
//       Thread1: WaitSleepJoin
//       Thread2: Running
//
//
//       Current thread: Thread1
//       Thread1: Running
//       Thread2: Stopped

Imports System.Threading

Module Example
   Dim thread1, thread2 As Thread

   Public Sub Main()
      thread1 = new Thread(AddressOf ThreadProc)
      thread1.Name = "Thread1"
      thread1.Start()
      
      thread2 = New Thread(AddressOf ThreadProc)
      thread2.Name = "Thread2"
      thread2.Start()   
   End Sub

   Private Sub ThreadProc()
      Console.WriteLine()
      Console.WriteLine("Current thread: {0}", Thread.CurrentThread.Name)
      If (Thread.CurrentThread.Name = "Thread1" And 
          thread2.ThreadState <> ThreadState.Unstarted)
         thread2.Join()
      End If
      Thread.Sleep(4000)
      Console.WriteLine()
      Console.WriteLine("Current thread: {0}", Thread.CurrentThread.Name)
      Console.WriteLine("Thread1: {0}", thread1.ThreadState)
      Console.WriteLine("Thread2: {0}", thread2.ThreadState)
      Console.WriteLine()
   End Sub
End Module
' The example displays output like the following :
'       Current thread: Thread1
'       
'       Current thread: Thread2
'       
'       Current thread: Thread2
'       Thread1: WaitSleepJoin
'       Thread2: Running
'       
'       
'       Current thread: Thread1
'       Thread1: Running
'       Thread2: Stopped

如果在调用时 Join 线程已终止，该方法将立即返回。

警告

永远不要从当前 Join 线程调用表示当前线程的对象的方法 Thread 。这会导致应用无响应，因为当前线程无限期地等待自身，

此方法将调用线程的状态更改为包含 ThreadState.WaitSleepJoin。不能在处于状态ThreadState.Unstarted的线程上调用 Join 。

另请参阅

ThreadState

适用于

.NET 10 和其他版本

产品	版本
.NET	Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9, 10
.NET Framework	1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard	2.0, 2.1

Join(Int32)

Source:: Thread.cs

Source:: Thread.cs

Source:: Thread.cs

在继续执行标准的 COM 和 SendMessage 消息泵处理期间，阻止调用线程，直到由该实例表示的线程终止或经过了指定时间为止。

public:
 bool Join(int millisecondsTimeout);

public bool Join(int millisecondsTimeout);

member this.Join : int -> bool

Public Function Join (millisecondsTimeout As Integer) As Boolean

参数

millisecondsTimeout: Int32

等待线程终止的毫秒数。

Boolean

如果线程已终止，则为 true；如果 false 参数指定的时间量已过之后还未终止线程，则为 millisecondsTimeout。

例外

ArgumentOutOfRangeException

millisecondsTimeout 的值为负数，且不等于 Infinite（以毫秒为单位）。

ThreadStateException

该线程尚未启动。

ArgumentException

millisecondsTimeout 小于 -1 (Timeout.Infinite)。

ThreadInterruptedException

线程在等待时中断。

注解

Join(Int32) 是阻止调用线程的同步方法 (即调用方法的线程) ，直到调用其方法的 Join 线程已完成或超时间隔已过。在下面的示例中 Thread1 ，线程调用 Join() 的 Thread2方法，这会导致 Thread1 阻塞直到 Thread2 完成或 2 秒已过。

using System;
using System.Threading;

public class Example
{
   static Thread thread1, thread2;
   
   public static void Main()
   {
      thread1 = new Thread(ThreadProc);
      thread1.Name = "Thread1";
      thread1.Start();
      
      thread2 = new Thread(ThreadProc);
      thread2.Name = "Thread2";
      thread2.Start();   
   }

   private static void ThreadProc()
   {
      Console.WriteLine("\nCurrent thread: {0}", Thread.CurrentThread.Name);
      if (Thread.CurrentThread.Name == "Thread1" && 
          thread2.ThreadState != ThreadState.Unstarted)
         if (thread2.Join(2000))
            Console.WriteLine("Thread2 has termminated.");
         else
            Console.WriteLine("The timeout has elapsed and Thread1 will resume.");   
      
      Thread.Sleep(4000);
      Console.WriteLine("\nCurrent thread: {0}", Thread.CurrentThread.Name);
      Console.WriteLine("Thread1: {0}", thread1.ThreadState);
      Console.WriteLine("Thread2: {0}\n", thread2.ThreadState);
   }
}
// The example displays the following output:
//       Current thread: Thread1
//       
//       Current thread: Thread2
//       The timeout has elapsed and Thread1 will resume.
//       
//       Current thread: Thread2
//       Thread1: WaitSleepJoin
//       Thread2: Running
//       
//       
//       Current thread: Thread1
//       Thread1: Running
//       Thread2: Stopped

open System.Threading

let mutable thread1, thread2 =
    Unchecked.defaultof<Thread>, Unchecked.defaultof<Thread>

let threadProc () =
    printfn $"\nCurrent thread: {Thread.CurrentThread.Name}"

    if
        Thread.CurrentThread.Name = "Thread1"
        && thread2.ThreadState <> ThreadState.Unstarted
    then
        if thread2.Join 2000 then
            printfn "Thread2 has termminated."
        else
            printfn "The timeout has elapsed and Thread1 will resume."

    Thread.Sleep 4000
    printfn $"\nCurrent thread: {Thread.CurrentThread.Name}"
    printfn $"Thread1: {thread1.ThreadState}"
    printfn $"Thread2: {thread2.ThreadState}\n"

thread1 <- Thread threadProc
thread1.Name <- "Thread1"
thread1.Start()

thread2 <- Thread threadProc
thread2.Name <- "Thread2"
thread2.Start()

// The example displays the following output:
//       Current thread: Thread1
//
//       Current thread: Thread2
//       The timeout has elapsed and Thread1 will resume.
//
//       Current thread: Thread2
//       Thread1: WaitSleepJoin
//       Thread2: Running
//
//
//       Current thread: Thread1
//       Thread1: Running
//       Thread2: Stopped

Imports System.Threading

Module Example
   Dim thread1, thread2 As Thread

   Public Sub Main()
      thread1 = new Thread(AddressOf ThreadProc)
      thread1.Name = "Thread1"
      thread1.Start()
      
      thread2 = New Thread(AddressOf ThreadProc)
      thread2.Name = "Thread2"
      thread2.Start()   
   End Sub

   Private Sub ThreadProc()
      Console.WriteLine()
      Console.WriteLine("Current thread: {0}", Thread.CurrentThread.Name)
      If (Thread.CurrentThread.Name = "Thread1" And 
          thread2.ThreadState <> ThreadState.Unstarted)
         If thread2.Join(TimeSpan.FromSeconds(2))
            Console.WriteLine("Thread2 has termminated.")
         Else
            Console.WriteLine("The timeout has elapsed and Thread1 will resume.")
         End If      
      End If
      Thread.Sleep(4000)
      Console.WriteLine()
      Console.WriteLine("Current thread: {0}", Thread.CurrentThread.Name)
      Console.WriteLine("Thread1: {0}", thread1.ThreadState)
      Console.WriteLine("Thread2: {0}", thread2.ThreadState)
      Console.WriteLine()
   End Sub
End Module
' The example displays the following output:
'       Current thread: Thread1
'       
'       Current thread: Thread2
'       
'       Current thread: Thread2
'       Thread1: WaitSleepJoin
'       Thread2: Running
'       
'       
'       Current thread: Thread1
'       Thread1: Running
'       Thread2: Stopped

如果 Timeout.Infinite 为 millisecondsTimeout 参数指定了，则此方法的行为与 Join() 方法重载相同，但返回值除外。

如果在调用时 Join 线程已终止，该方法将立即返回。

此方法将调用线程的状态更改为包含 ThreadState.WaitSleepJoin。不能在处于状态ThreadState.Unstarted的线程上调用 Join 。

另请参阅

ThreadState

适用于

.NET 10 和其他版本

产品	版本
.NET	Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9, 10
.NET Framework	1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard	2.0, 2.1

Join(TimeSpan)

Source:: Thread.cs

Source:: Thread.cs

Source:: Thread.cs

在继续执行标准的 COM 和 SendMessage 消息泵处理期间，阻止调用线程，直到由该实例表示的线程终止或经过了指定时间为止。

public:
 bool Join(TimeSpan timeout);

public bool Join(TimeSpan timeout);

member this.Join : TimeSpan -> bool

Public Function Join (timeout As TimeSpan) As Boolean

参数

timeout: TimeSpan

设置等待线程终止的时间量的 TimeSpan。

Boolean

如果线程已终止，则为 true；如果 false 参数指定的时间量已过之后还未终止线程，则为 timeout。

例外

ArgumentOutOfRangeException

的值为 timeout 负，不等于 Infinite 以毫秒为单位，或大于 Int32.MaxValue 毫秒。

ThreadStateException

调用方尝试加入处于 Unstarted 状态的线程。

示例

下面的代码示例演示如何将值与方法一 TimeSpan 起使用 Join 。

using namespace System;
using namespace System::Threading;

static TimeSpan waitTime = TimeSpan(0,0,1);

ref class Test
{
public:
   static void Work()
   {
      Thread::Sleep( waitTime );
   }

};

int main()
{
   Thread^ newThread = gcnew Thread( gcnew ThreadStart( Test::Work ) );
   newThread->Start();
   if ( newThread->Join( waitTime + waitTime ) )
   {
      Console::WriteLine( "New thread terminated." );
   }
   else
   {
      Console::WriteLine( "Join timed out." );
   }
}
// The example displays the following output:
//        New thread terminated.

using System;
using System.Threading;

class Test
{
    static TimeSpan waitTime = new TimeSpan(0, 0, 1);

    public static void Main() 
    {
        Thread newThread = new Thread(Work);
        newThread.Start();

        if(newThread.Join(waitTime + waitTime)) {
            Console.WriteLine("New thread terminated.");
        }
        else {
            Console.WriteLine("Join timed out.");
        }
    }

    static void Work()
    {
        Thread.Sleep(waitTime);
    }
}
// The example displays the following output:
//        New thread terminated.

open System
open System.Threading

let waitTime = TimeSpan(0, 0, 1)

let work () =
    Thread.Sleep waitTime

let newThread = Thread work
newThread.Start()

if waitTime + waitTime |> newThread.Join then
    printfn "New thread terminated."
else
    printfn "Join timed out."

// The example displays the following output:
//        New thread terminated.

Imports System.Threading

Public Module Test
    Dim waitTime As New TimeSpan(0, 0, 1)

    Public Sub Main() 
        Dim newThread As New Thread(AddressOf Work)
        newThread.Start()

        If newThread.Join(waitTime + waitTime) Then
            Console.WriteLine("New thread terminated.")
        Else
            Console.WriteLine("Join timed out.")
        End If
    End Sub

    Private Sub Work()
        Thread.Sleep(waitTime)
    End Sub
End Module
' The example displays the following output:
'       New thread terminated.

注解

Join(TimeSpan) 是阻止调用线程的同步方法 (即调用方法的线程) ，直到调用其方法的 Join 线程已完成或超时间隔已过。在下面的示例中 Thread1 ，线程调用 Join() 的 Thread2方法，这会导致 Thread1 阻塞直到 Thread2 完成或 2 秒已过。

using System;
using System.Threading;

public class Example
{
   static Thread thread1, thread2;
   
   public static void Main()
   {
      thread1 = new Thread(ThreadProc);
      thread1.Name = "Thread1";
      thread1.Start();
      
      thread2 = new Thread(ThreadProc);
      thread2.Name = "Thread2";
      thread2.Start();   
   }

   private static void ThreadProc()
   {
      Console.WriteLine("\nCurrent thread: {0}", Thread.CurrentThread.Name);
      if (Thread.CurrentThread.Name == "Thread1" && 
          thread2.ThreadState != ThreadState.Unstarted)
         if (thread2.Join(TimeSpan.FromSeconds(2)))
            Console.WriteLine("Thread2 has termminated.");
         else
            Console.WriteLine("The timeout has elapsed and Thread1 will resume.");   
      
      Thread.Sleep(4000);
      Console.WriteLine("\nCurrent thread: {0}", Thread.CurrentThread.Name);
      Console.WriteLine("Thread1: {0}", thread1.ThreadState);
      Console.WriteLine("Thread2: {0}\n", thread2.ThreadState);
   }
}
// The example displays the following output:
//       Current thread: Thread1
//       
//       Current thread: Thread2
//       The timeout has elapsed and Thread1 will resume.
//       
//       Current thread: Thread2
//       Thread1: WaitSleepJoin
//       Thread2: Running
//       
//       
//       Current thread: Thread1
//       Thread1: Running
//       Thread2: Stopped

open System
open System.Threading

let mutable thread1, thread2 =
    Unchecked.defaultof<Thread>, Unchecked.defaultof<Thread>

let threadProc () =
    printfn $"\nCurrent thread: {Thread.CurrentThread.Name}"

    if
        Thread.CurrentThread.Name = "Thread1"
        && thread2.ThreadState <> ThreadState.Unstarted
    then
        if TimeSpan.FromSeconds 2 |> thread2.Join then
            printfn "Thread2 has termminated."
        else
            printfn "The timeout has elapsed and Thread1 will resume."

    Thread.Sleep 4000
    printfn $"\nCurrent thread: {Thread.CurrentThread.Name}"
    printfn $"Thread1: {thread1.ThreadState}"
    printfn $"Thread2: {thread2.ThreadState}\n"

thread1 <- Thread threadProc
thread1.Name <- "Thread1"
thread1.Start()

thread2 <- Thread threadProc
thread2.Name <- "Thread2"
thread2.Start()

// The example displays the following output:
//       Current thread: Thread1
//
//       Current thread: Thread2
//       The timeout has elapsed and Thread1 will resume.
//
//       Current thread: Thread2
//       Thread1: WaitSleepJoin
//       Thread2: Running
//
//
//       Current thread: Thread1
//       Thread1: Running
//       Thread2: Stopped

Imports System.Threading

Module Example
   Dim thread1, thread2 As Thread

   Public Sub Main()
      thread1 = new Thread(AddressOf ThreadProc)
      thread1.Name = "Thread1"
      thread1.Start()
      
      thread2 = New Thread(AddressOf ThreadProc)
      thread2.Name = "Thread2"
      thread2.Start()   
   End Sub

   Private Sub ThreadProc()
      Console.WriteLine()
      Console.WriteLine("Current thread: {0}", Thread.CurrentThread.Name)
      If (Thread.CurrentThread.Name = "Thread1" And 
          thread2.ThreadState <> ThreadState.Unstarted)
         If thread2.Join(2000)
            Console.WriteLine("Thread2 has termminated.")
         Else
            Console.WriteLine("The timeout has elapsed and Thread1 will resume.")
         End If      
      End If
      Thread.Sleep(4000)
      Console.WriteLine()
      Console.WriteLine("Current thread: {0}", Thread.CurrentThread.Name)
      Console.WriteLine("Thread1: {0}", thread1.ThreadState)
      Console.WriteLine("Thread2: {0}", thread2.ThreadState)
      Console.WriteLine()
   End Sub
End Module
' The example displays the following output:
'       Current thread: Thread1
'       
'       Current thread: Thread2
'       
'       Current thread: Thread2
'       Thread1: WaitSleepJoin
'       Thread2: Running
'       
'       
'       Current thread: Thread1
'       Thread1: Running
'       Thread2: Stopped

如果 Timeout.Infinite 为 timeout指定了，则此方法的行为与 Join() 方法重载相同，但返回值除外。

如果在调用时 Join 线程已终止，该方法将立即返回。

此方法将当前线程的状态更改为包含 WaitSleepJoin。不能在处于状态ThreadState.Unstarted的线程上调用 Join 。

另请参阅

ThreadState

适用于

.NET 10 和其他版本

产品	版本
.NET	Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9, 10
.NET Framework	1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard	2.0, 2.1

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连接、编码和成长

通过

Thread.Join 方法

定义

重载

Join()

例外

注解

另请参阅

适用于

Join(Int32)

参数

返回

例外

注解

另请参阅

适用于

Join(TimeSpan)

参数

返回

例外

示例

注解

另请参阅

适用于