c# 线程状态及转换

c#中我们可以使用System.Threading.Thread类来创建并启动一个线程，例子如下

Thread thread = new Thread(new ThreadStart(Execute1));thread.Start(); public void Execute1(){ Thread.Sleep(10000); }

Thread类通过ThreadState变量来代表线程当前的状态。 ThreadState是一个带flag特性的枚举变量，因此判断线程当前的状态，必须使用bitmask。作为一个特例，由于Running状态的bit码是0，因此，需要用如下方式判断线程是否处于运行状态：(thread.ThreadState & (ThreadState.Stopped | ThreadState.Unstarted)) == 0

线程状态值

System.Threading.ThreadState(enum):

ThreadState

Summary

Running=0The thread has been started, it is not blocked, and there is no pending System.Threading.ThreadAbortException

StopRequested = 1The thread is being requested to stop. This is for internal use only.

SuspendRequested = 2The thread is being requested to suspend.

Background = 4

The thread is being executed as a background thread, as opposed to a foreground thread. This state is controlled by setting the System.Thread

ing.Thread.IsBackground property.

Unstarted = 8The System.Threading.Thread.Start() method has not been invoked on the thread.

Stopped = 16The thread has stopped

WaitSleepJoin = 32The thread is blocked. This could be the result of calling System.Threading.Thread.Sleep(System.Int32)  or System.Threading.Thread.Join(), of requesting a lock — for example, by  calling System.Threading.Monitor.Enter(System.Object) or System.Threading.Monitor.Wait(System.Object,System.Int32,System.Boolean)   — or of waiting on a thread synchronization object such as System.Threading.ManualResetEvent.

Suspended = 64The thread has been suspended.

AbortRequested = 128The System.Threading.Thread.Abort(System.Object) method has been invoked on the thread, but the thread has not yet received the pending System.Threading.ThreadAbortException  that will attempt to terminate it.

Aborted = 256The thread state includes System.Threading.ThreadState.AbortRequested and the thread is now dead, but its state has not yet changed to System.Threading.ThreadState.Stopped.

状态转换图

Join线程

当调用线程的Join()函数时，将会阻塞当前调用线程直到被Join线程结束，

如果在调用Join()函数之前，该线程已经运行结束，当前调用线程不会被阻塞。

public void Test4() { Thread thread1 = new Thread(new ThreadStart(Execute4_1)); Console.WriteLine("ThreadStatus1:" + thread1.ThreadState); thread1.Start(); Console.WriteLine("ThreadStatus1:" + thread1.ThreadState); thread1.Join(); Console.WriteLine("ThreadStatus1:" + thread1.ThreadState); } public void Execute4_1() { Console.WriteLine("Execute4_1 started"); Thread.Sleep(10000); Console.WriteLine("Execute4_1 finished"); }

控制台输出:

ThreadStatus1:Unstarted

ThreadStatus1:Running

Execute4_1 started

Execute4_1 finished

ThreadStatus1:Stopped

Abort线程

当调用线程的Abort函数时，在线程内部将会触发一个System.Threading.ThreadAbortException，线程内部可以catch该异常来进行线程终结处理。

object test5Lock = new object(); Thread thread1 = null; Thread thread2 = null; public void Test5() { thread1 = new Thread(new ThreadStart(Execute5_1)); Console.WriteLine("ThreadStatus1:" + thread1.ThreadState); thread1.Start(); Console.WriteLine("ThreadStatus1:" + thread1.ThreadState); thread2 = new Thread(new ThreadStart(Execute5_2)); Console.WriteLine("ThreadStatus2:" + thread1.ThreadState); thread2.Start(); Console.WriteLine("ThreadStatus2:" + thread1.ThreadState); } public void Execute5_1() { try { while (true) { Monitor.Enter(test5Lock); Console.WriteLine("Execute5_1"); } } catch (ThreadAbortException e) { Console.WriteLine("ThreadAbortException"); Console.WriteLine(e.StackTrace); } catch (ThreadInterruptedException e) { Console.WriteLine("ThreadInterruptedException"); Console.WriteLine(e.StackTrace); } } public void Execute5_2() { Thread.Sleep(5000); thread1.Abort("Test"); }

控制台输出:

ThreadStatus1:Unstarted

ThreadStatus1:Running

ThreadStatus2:Unstarted

ThreadStatus2:Running

ThreadAbortException

at System.Threading.Monitor.Enter(Object obj)

at ThreadResearch.ThreadStatusTest.Execute5_1() in E:\MyWorkspace\Projects\CS

harpBasicLib\ThreadResearch\ThreadStatusTest.cs:line 145

ThreadStatus1:Aborted

Interrupt线程

当被调用线程处于WaitSleepJoin状态时，调用Interrupt()函数，在线程内部将会抛出ThreadInterruptedException，否则什么事情也不会发生。

object test5Lock = new object(); Thread thread1 = null; Thread thread2 = null; public void Test5() { Thread thread3 = new Thread(new ThreadStart(Execute5_3)); thread3.Start(); Thread.Sleep(1000); thread1 = new Thread(new ThreadStart(Execute5_1)); Console.WriteLine("ThreadStatus1:" + thread1.ThreadState); thread1.Start(); Console.WriteLine("ThreadStatus1:" + thread1.ThreadState); thread2 = new Thread(new ThreadStart(Execute5_2)); Console.WriteLine("ThreadStatus2:" + thread2.ThreadState); thread2.Start(); Console.WriteLine("ThreadStatus2:" + thread2.ThreadState); thread1.Join(); Console.WriteLine("ThreadStatus1:" + thread1.ThreadState); } public void Execute5_1() { try { while (true) { Monitor.Enter(test5Lock); } } catch (ThreadAbortException e) { Console.WriteLine("ThreadAbortException"); Console.WriteLine(e.StackTrace); } catch (ThreadInterruptedException e) { Console.WriteLine("ThreadInterruptedException"); Console.WriteLine(e.StackTrace); } } public void Execute5_2() { Thread.Sleep(5000); thread1.Interrupt(); //thread1.Abort("Test"); } public void Execute5_3() { Monitor.Enter(test5Lock); Thread.Sleep(100000); }

控制台输出:

ThreadStatus1:Unstarted

ThreadStatus1:Running

ThreadStatus2:Unstarted

ThreadStatus2:Running

ThreadInterruptedException

at System.Threading.Monitor.Enter(Object obj)

at ThreadResearch.ThreadStatusTest.Execute5_1() in E:\MyWorkspace\Projects\CS

harpBasicLib\ThreadResearch\ThreadStatusTest.cs:line 149

ThreadStatus1:Stopped