This enumeration encapsulates the various states a thread may be in. A thread starts in the Unstarted state. Once the Thread.Start( ) method is called, a thread enters the Running state. If another thread calls Thread.Abort( ) at any time, the thread shifts into the AbortRequested state, and then into Aborted once the thread reaches a safe point for garbage collection.

If the running thread calls either the static method Thread.Sleep( ), any of the Wait( ) methods on a WaitHandle, or Thread.Join( ) on another thread, the executing thread enters the WaitSleepJoin state.

If another thread calls Thread.Interrupt( ) on a thread in the WaitSleepJoin state, the thread again enters the Running state. When another thread calls Thread.Suspend( ) on a thread, it enters the SuspendRequested state. Once a thread in the SuspendRequested state reaches a safe point for garbage collection, it enters the Suspended state. A thread then leaves the Suspended state and enters the running state when another thread calls Thread.Resume( ) on it. When a thread has finished running, it enters the Stopped state.

Once a thread has started, it cannot return to the Unstarted state. Similarly, once a thread has aborted or stopped, it cannot return to the Running state. This enumeration is marked with a [Flags( )] attribute, which allows a thread to be in more than one state at a time. For example, if a thread is in the WaitSleepJoin and another thread calls Thread.Abort( ) on it, it will be in both the WaitSleepJoin and AbortRequested states at the same time.

public enum ThreadState {
   Running = 0x00000000,
   StopRequested = 0x00000001,
   SuspendRequested = 0x00000002,
   Background = 0x00000004,
   Unstarted = 0x00000008,
   Stopped = 0x00000010,
   WaitSleepJoin = 0x00000020,
   Suspended = 0x00000040,
   AbortRequested = 0x00000080,
   Aborted = 0x00000100
}

Hierarchy

System.Object System.ValueType System.Enum(System.IComparable, System.IFormattable, System.IConvertible) ThreadState

Returned By

Thread.ThreadState