public enum class ThreadState
[System.Flags] [System.Runtime.InteropServices.ComVisible(true)] public enum ThreadState
type ThreadState =
Public Enum ThreadState
|Aborted Aborted Aborted Aborted||256|
|AbortRequested AbortRequested AbortRequested AbortRequested||128|
|Background Background Background Background||4||
The thread is being executed as a background thread, as opposed to a foreground thread. This state is controlled by setting the IsBackground property.
|Running Running Running Running||0||
The thread has been started, it is not blocked, and there is no pending ThreadAbortException.
|Stopped Stopped Stopped Stopped||16||
The thread has stopped.
|StopRequested StopRequested StopRequested StopRequested||1||
The thread is being requested to stop. This is for internal use only.
|Suspended Suspended Suspended Suspended||64||
The thread has been suspended.
|SuspendRequested SuspendRequested SuspendRequested SuspendRequested||2||
The thread is being requested to suspend.
|Unstarted Unstarted Unstarted Unstarted||8||
The Start() method has not been invoked on the thread.
|WaitSleepJoin WaitSleepJoin WaitSleepJoin WaitSleepJoin||32||
The thread is blocked. This could be the result of calling Sleep(Int32) or Join(), of requesting a lock — for example, by calling Enter(Object) or Wait(Object, Int32, Boolean) — or of waiting on a thread synchronization object such as ManualResetEvent.
The ThreadState enumeration is of interest only in a few debugging scenarios. Your code should never use the thread state to synchronize the activities of threads.
ThreadState defines a set of all possible execution states for threads. Once a thread is created, it is in at least one of the states until it terminates. Threads created within the common language runtime are initially in the
Unstarted state, while external threads that come into the runtime are already in the
Running state. An
Unstarted thread is transitioned into the
Running state by calling Start. Not all combinations of
ThreadState values are valid; for example, a thread cannot be in both the
The following table shows the actions that cause a change of state.
|A thread is created within the common language runtime.||Unstarted|
|Another thread calls the Thread.Start method on the new thread, and the call returns.
The Start method does not return until the new thread has started running. There is no way to know at what point the new thread will start running, during the call to Start.
|The thread calls Sleep||WaitSleepJoin|
|The thread calls Wait on another object.||WaitSleepJoin|
|The thread calls Join on another thread.||WaitSleepJoin|
|Another thread calls Interrupt||Running|
|Another thread calls Suspend||SuspendRequested|
|The thread responds to a Suspend request.||Suspended|
|Another thread calls Resume||Running|
|Another thread calls Abort||AbortRequested|
|The thread responds to a Abort request.||Stopped|
|A thread is terminated.||Stopped|
In addition to the states noted above, there is also the
Background state, which indicates whether the thread is running in the background or foreground.
A thread can be in more than one state at a given time. For example, if a thread is blocked on a call to Wait, and another thread calls Abort on the blocked thread, the blocked thread will be in both the
WaitSleepJoin and the
AbortRequested states at the same time. In this case, as soon as the thread returns from the call to Wait or is interrupted, it will receive the ThreadAbortException to begin aborting.
The Thread.ThreadState property of a thread provides the current state of a thread. Applications must use a bitmask to determine whether a thread is running. Since the value for
Running is zero (0), test whether a thread is running by using C# code such as
(myThread.ThreadState & (ThreadState.Stopped | ThreadState.Unstarted)) == 0 or Visual Basic code such as
(myThread.ThreadState And (ThreadState.Stopped Or ThreadState.Unstarted)) = 0.