ThreadPriority 枚举

项目
08/17/2007

指定 Thread 的调度优先级。

**命名空间:**System.Threading
**程序集:**mscorlib（在 mscorlib.dll 中）

语法

声明
<SerializableAttribute> _
<ComVisibleAttribute(True)> _
Public Enumeration ThreadPriority
用法
Dim instance As ThreadPriority

[SerializableAttribute] 
[ComVisibleAttribute(true)] 
public enum ThreadPriority

[SerializableAttribute] 
[ComVisibleAttribute(true)] 
public enum class ThreadPriority

/** @attribute SerializableAttribute() */ 
/** @attribute ComVisibleAttribute(true) */ 
public enum ThreadPriority

SerializableAttribute 
ComVisibleAttribute(true) 
public enum ThreadPriority

成员

	成员名称	说明
	AboveNormal	可以将 Thread 安排在具有 Highest 优先级的线程之后，在具有 Normal 优先级的线程之前。
	BelowNormal	可以将 Thread 安排在具有 Normal 优先级的线程之后，在具有 Lowest 优先级的线程之前。
	Highest	可以将 Thread 安排在具有任何其他优先级的线程之前。
	Lowest	可以将 Thread 安排在具有任何其他优先级的线程之后。
	Normal	可以将 Thread 安排在具有 AboveNormal 优先级的线程之后，在具有 BelowNormal 优先级的线程之前。默认情况下，线程具有 Normal 优先级。

备注

ThreadPriority 定义一组线程优先级的所有可能值。线程优先级指定一个线程相对于另一个线程的相对优先级。

每个线程都有一个分配的优先级。在运行库内创建的线程最初被分配 Normal 优先级，而在运行库外创建的线程在进入运行库时将保留其先前的优先级。可以通过访问线程的 Priority 属性来获取和设置其优先级。

根据线程的优先级调度线程的执行。用于确定线程执行顺序的调度算法随操作系统的不同而不同。操作系统也可以在用户界面的焦点在前台和后台之间移动时动态地调整线程的优先级。

一个线程的优先级不影响该线程的状态；该线程的状态在操作系统可以调度该线程之前必须为 Running。

示例

下面的代码示例说明了更改线程优先级的结果。创建两个线程，其中一个线程的优先级设置为 BelowNormal。两个线程在 while 循环中都增加一个变量，并运行一段设定的时间。

Option Explicit
Option Strict

Imports System
Imports System.Threading

Public Class Test

    <MTAThread> _
    Shared Sub Main()
        Dim priorityTest As New PriorityTest()

        Dim threadOne As Thread = _
            New Thread(AddressOf priorityTest.ThreadMethod)
        threadOne.Name = "ThreadOne"
        Dim threadTwo As Thread = _
            New Thread(AddressOf priorityTest.ThreadMethod)
        threadTwo.Name = "ThreadTwo"

        threadTwo.Priority = ThreadPriority.BelowNormal
        threadOne.Start()
        threadTwo.Start()

        ' Allow counting for 10 seconds.
        Thread.Sleep(10000)
        priorityTest.LoopSwitch = False
    End Sub

End Class

Public Class PriorityTest

    Dim loopSwitchValue As Boolean 

    Sub New()
        loopSwitchValue = True
    End Sub

    WriteOnly Property LoopSwitch As Boolean
        Set
            loopSwitchValue = Value
        End Set
    End Property

    Sub ThreadMethod()
        Dim threadCount As Long = 0

        While loopSwitchValue
            threadCount += 1
        End While
        
        Console.WriteLine("{0} with {1,11} priority " & _
            "has a count = {2,13}", Thread.CurrentThread.Name, _
            Thread.CurrentThread.Priority.ToString(), _
            threadCount.ToString("N0")) 
    End Sub

End Class

using System;
using System.Threading;

class Test
{
    static void Main()
    {
        PriorityTest priorityTest = new PriorityTest();
        ThreadStart startDelegate = 
            new ThreadStart(priorityTest.ThreadMethod);

        Thread threadOne = new Thread(startDelegate);
        threadOne.Name = "ThreadOne";
        Thread threadTwo = new Thread(startDelegate);
        threadTwo.Name = "ThreadTwo";

        threadTwo.Priority = ThreadPriority.BelowNormal;
        threadOne.Start();
        threadTwo.Start();

        // Allow counting for 10 seconds.
        Thread.Sleep(10000);
        priorityTest.LoopSwitch = false;
    }
}

class PriorityTest
{
    bool loopSwitch;

    public PriorityTest()
    {
        loopSwitch = true;
    }

    public bool LoopSwitch
    {
        set{ loopSwitch = value; }
    }

    public void ThreadMethod()
    {
        long threadCount = 0;

        while(loopSwitch)
        {
            threadCount++;
        }
        Console.WriteLine("{0} with {1,11} priority " +
            "has a count = {2,13}", Thread.CurrentThread.Name, 
            Thread.CurrentThread.Priority.ToString(), 
            threadCount.ToString("N0")); 
    }
}

using namespace System;
using namespace System::Threading;
ref class PriorityTest
{
private:
   bool loopSwitch;

public:
   PriorityTest()
   {
      loopSwitch = true;
   }


   property bool LoopSwitch 
   {
      void set( bool value )
      {
         loopSwitch = value;
      }

   }
   void ThreadMethod()
   {
      __int64 threadCount = 0;
      while ( loopSwitch )
      {
         threadCount++;
      }

      Console::WriteLine( "{0} with {1,11} priority "
      "has a count = {2,13}", Thread::CurrentThread->Name, Thread::CurrentThread->Priority.ToString(), threadCount.ToString(  "N0" ) );
   }

};

int main()
{
   PriorityTest^ priorityTest = gcnew PriorityTest;
   ThreadStart^ startDelegate = gcnew ThreadStart( priorityTest, &PriorityTest::ThreadMethod );
   Thread^ threadOne = gcnew Thread( startDelegate );
   threadOne->Name =  "ThreadOne";
   Thread^ threadTwo = gcnew Thread( startDelegate );
   threadTwo->Name =  "ThreadTwo";
   threadTwo->Priority = ThreadPriority::BelowNormal;
   threadOne->Start();
   threadTwo->Start();
   
   // Allow counting for 10 seconds.
   Thread::Sleep( 10000 );
   priorityTest->LoopSwitch = false;
}

import System.*;
import System.Threading.*;
import System.Threading.Thread;

class Test
{
    public static void main(String[] args)
    {
        PriorityTest priorityTest = new PriorityTest();
        ThreadStart startDelegate = new ThreadStart(priorityTest.ThreadMethod);
        Thread threadOne = new Thread(startDelegate);

        threadOne.set_Name("ThreadOne");

        Thread threadTwo = new Thread(startDelegate);

        threadTwo.set_Name("ThreadTwo");
        threadTwo.set_Priority(ThreadPriority.BelowNormal);
        threadOne.Start();
        threadTwo.Start();

        // Allow counting for 10 seconds.
        Thread.Sleep(10000);
        priorityTest.set_LoopSwitch(false);
    } //main
} //Test

class PriorityTest
{
    private boolean loopSwitch;

    public PriorityTest()
    {
        loopSwitch = true;
    } //PriorityTest

    /** @property 
     */
    public void set_LoopSwitch(boolean value)
    {
        loopSwitch = value;
    } //set_LoopSwitch

    public void ThreadMethod()
    {
        long threadCount = 0;

        while (loopSwitch) {
            threadCount++;
        }

        Console.WriteLine("{0} with {1,11} priority " + "has a count = {2,13}",
            Thread.get_CurrentThread().get_Name(),
            Thread.get_CurrentThread().get_Priority().toString(),
            ((System.Int32)threadCount).ToString("N0"));
    } //ThreadMethod
} //PriorityTest

平台

Windows 98、Windows 2000 SP4、Windows CE、Windows Millennium Edition、Windows Mobile for Pocket PC、Windows Mobile for Smartphone、Windows Server 2003、Windows XP Media Center Edition、Windows XP Professional x64 Edition、Windows XP SP2、Windows XP Starter Edition

.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表，请参见系统要求。

ThreadPriority 枚举

语法

成员

备注

示例

平台

版本信息

.NET Framework

.NET Compact Framework

请参见

参考

其他资源

其他资源