Thread.ThreadState Property

Gets a value containing the states of the current thread.

Namespace:  System.Threading
Assembly:  mscorlib (in mscorlib.dll)

'Declaration
Public ReadOnly Property ThreadState As ThreadState

Property Value

Type: System.Threading.ThreadState
One of the ThreadState values indicating the state of the current thread. The initial value is Unstarted.

The ThreadState property provides more specific information than the IsAlive property.

Important noteImportant

Thread state is only of interest in debugging scenarios. Your code should never use thread state to synchronize the activities of threads.

The following code example demonstrates accessing the ThreadState of a thread.

Imports Microsoft.VisualBasic
Imports System
Imports System.Threading

Public Class ApartmentTest

    <MTAThread> _
    Shared Sub Main()

        Dim newThread As Thread = New Thread(AddressOf ThreadMethod)
        newThread.SetApartmentState(ApartmentState.MTA)

        ' The following line is ignored since  
        ' ApartmentState can only be set once.
        newThread.SetApartmentState(ApartmentState.STA)

        Console.WriteLine("ThreadState: {0}, ApartmentState: {1}", _
            newThread.ThreadState, newThread.GetApartmentState())

        newThread.Start()

        ' Wait for newThread to start and go to sleep.
        Thread.Sleep(300)
        Try 
            ' This causes an exception since newThread is sleeping.
            newThread.SetApartmentState(ApartmentState.STA)
        Catch stateException As ThreadStateException
            Console.WriteLine(vbCrLf & "{0} caught:" & vbCrLf & _
                "Thread is not In the Unstarted or Running state.", _
                stateException.GetType().Name)
            Console.WriteLine("ThreadState: {0}, ApartmentState: " & _
                "{1}", newThread.ThreadState, newThread.GetApartmentState())
        End Try 

    End Sub 

    Shared Sub ThreadMethod()
        Thread.Sleep(1000)
    End Sub 

End Class

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone 8, Silverlight 8.1

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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