ThreadPriority 枚举
定义
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。
指定 Thread 的调度优先级。
public enum class ThreadPrioritypublic enum ThreadPriority[System.Serializable]
public enum ThreadPriority[System.Serializable]
[System.Runtime.InteropServices.ComVisible(true)]
public enum ThreadPrioritytype ThreadPriority = [<System.Serializable>]
type ThreadPriority = [<System.Serializable>]
[<System.Runtime.InteropServices.ComVisible(true)>]
type ThreadPriority = Public Enum ThreadPriority- 继承
- 属性
字段
| AboveNormal | 3 | 可以将 Thread 安排在具有 |
| BelowNormal | 1 | 可以将 Thread 安排在具有 |
| Highest | 4 | 可以将 Thread 安排在具有任何其他优先级的线程之前。 |
| Lowest | 0 | 可以将 Thread 安排在具有任何其他优先级的线程之后。 |
| Normal | 2 | 可以将 Thread 安排在具有 |
示例
下面的代码示例显示了更改线程优先级的结果。 创建三个线程，一个线程的优先级设置为 BelowNormal，第二个线程的优先级设置为 AboveNormal。 每个线程在循环中递增一个 while 变量，并在设定的时间内运行。
using System;
using System.Threading;
using Timers = System.Timers;
class Test
{
static void Main()
{
PriorityTest priorityTest = new PriorityTest();
Thread thread1 = new Thread(priorityTest.ThreadMethod);
thread1.Name = "ThreadOne";
Thread thread2 = new Thread(priorityTest.ThreadMethod);
thread2.Name = "ThreadTwo";
thread2.Priority = ThreadPriority.BelowNormal;
Thread thread3 = new Thread(priorityTest.ThreadMethod);
thread3.Name = "ThreadThree";
thread3.Priority = ThreadPriority.AboveNormal;
thread1.Start();
thread2.Start();
thread3.Start();
// Allow counting for 10 seconds.
Thread.Sleep(10000);
priorityTest.LoopSwitch = false;
}
}
class PriorityTest
{
static volatile bool loopSwitch;
[ThreadStatic] static long threadCount = 0;
public PriorityTest()
{
loopSwitch = true;
}
public bool LoopSwitch
{
set{ loopSwitch = value; }
}
public void ThreadMethod()
{
while(loopSwitch)
{
threadCount++;
}
Console.WriteLine("{0,-11} with {1,11} priority " +
"has a count = {2,13}", Thread.CurrentThread.Name,
Thread.CurrentThread.Priority.ToString(),
threadCount.ToString("N0"));
}
}
// The example displays output like the following:
// ThreadOne with Normal priority has a count = 755,897,581
// ThreadThree with AboveNormal priority has a count = 778,099,094
// ThreadTwo with BelowNormal priority has a count = 7,840,984
Imports System.Threading
Imports Timers = System.Timers
Public Module Example
Dim t As Timers.Timer
Private priorityTest As New PriorityTest()
Public Sub Main()
Dim thread1 As New Thread(AddressOf priorityTest.ThreadMethod)
thread1.Name = "ThreadOne"
Dim thread2 As New Thread(AddressOf priorityTest.ThreadMethod)
thread2.Name = "ThreadTwo"
thread2.Priority = ThreadPriority.BelowNormal
Dim thread3 As New Thread(AddressOf priorityTest.ThreadMethod)
thread3.Name = "ThreadThree"
thread3.Priority = ThreadPriority.AboveNormal
thread1.Start()
thread2.Start()
thread3.Start()
' Allow threads to execute for about 10 seconds.
t = New Timers.Timer()
t.AutoReset = False
t.Interval = 10000
AddHandler t.Elapsed, AddressOf Elapsed
t.Start()
End Sub
Private Sub Elapsed(sender As Object, e As Timers.ElapsedEventArgs)
priorityTest.LoopSwitch = False
End Sub
End Module
Public Class PriorityTest
Private Shared loopSwitchValue As Boolean
<ThreadStatic> Shared threadCount As Long
Sub New()
loopSwitchValue = True
End Sub
WriteOnly Property LoopSwitch As Boolean
Set
loopSwitchValue = Value
End Set
End Property
Sub ThreadMethod()
Do While True
threadCount += 1
If Not loopSwitchValue Then Exit Do
Loop
Console.WriteLine("{0,-11} with {1,11} priority " &
"has a count = {2,13}", Thread.CurrentThread.Name,
Thread.CurrentThread.Priority.ToString(),
threadCount.ToString("N0"))
End Sub
End Class
' The example displays the following output:
' ThreadOne with Normal priority has a count = 755,897,581
' ThreadThree with AboveNormal priority has a count = 778,099,094
' ThreadTwo with BelowNormal priority has a count = 7,840,984
注解
ThreadPriority 定义线程优先级的所有可能值的集合。 线程优先级指定一个线程与另一个线程的相对优先级。
每个线程都有分配的优先级。 在运行时中创建的线程最初分配 Normal 优先级，而在运行时外部创建的线程在进入运行时时保留其以前的优先级。 可以通过访问 Priority 线程的 属性来获取和设置线程的优先级。
线程根据优先级被排入执行计划。 用于确定线程执行顺序的计划算法因操作系统而异。 当用户界面的焦点在前台和后台之间移动时，操作系统还可以动态调整线程优先级。
线程的优先级不会影响线程的状态;在操作系统可以计划线程之前，线程的状态必须为 Running 。