Thread.GetApartmentState Method

Definition

Namespace:

System.Threading

Assembly:

System.Threading.Thread.dll

Source:

Thread.CoreCLR.cs

Returns an ApartmentState value indicating the apartment state.

public:
 System::Threading::ApartmentState GetApartmentState();

public System.Threading.ApartmentState GetApartmentState ();

member this.GetApartmentState : unit -> System.Threading.ApartmentState

Public Function GetApartmentState () As ApartmentState

Returns

ApartmentState

One of the ApartmentState values indicating the apartment state of the managed thread. The default is Unknown.

Examples

The following code example demonstrates the GetApartmentState, SetApartmentState, and TrySetApartmentState methods. The code example creates a thread. Before the thread is started, GetApartmentState displays the initial ApartmentState.Unknown state and SetApartmentState changes the state to ApartmentState.STA. The TrySetApartmentState method then returns false when attempting to change the state to ApartmentState.MTA because the apartment state is already set. If the same operation had been attempted with SetApartmentState, InvalidOperationException would have been thrown.

After the thread is started, the TrySetApartmentState method is used again. This time it throws ThreadStateException because the thread has already been started.

using namespace System;
using namespace System::Threading;

void ThreadProc()
{
    Thread::Sleep(2000);
};

void main()
{
    Thread^ t = gcnew Thread(gcnew ThreadStart(ThreadProc));
    Console::WriteLine("Before setting apartment state: {0}", 
            t->GetApartmentState());

    t->SetApartmentState(ApartmentState::STA);
    Console::WriteLine("After setting apartment state: {0}", 
        t->GetApartmentState());

    bool result = t->TrySetApartmentState(ApartmentState::MTA);
    Console::WriteLine("Try to change state: {0}", result);

    t->Start();

    Thread::Sleep(500);

    try
    {
        t->TrySetApartmentState(ApartmentState::STA);
    }
    catch (ThreadStateException^)
    {
        Console::WriteLine("ThreadStateException occurs " +
            "if apartment state is set after starting thread.");
    }

    t->Join();
}

/* This code example produces the following output:

Before setting apartment state: Unknown
After setting apartment state: STA
Try to change state: False
ThreadStateException occurs if apartment state is set after starting thread.
 */

using System;
using System.Threading;

class Example
{
    public static void Main()
    {
        Thread t = new Thread(ThreadProc);
        Console.WriteLine("Before setting apartment state: {0}",
            t.GetApartmentState());

        t.SetApartmentState(ApartmentState.STA);
        Console.WriteLine("After setting apartment state: {0}",
            t.GetApartmentState());

        bool result = t.TrySetApartmentState(ApartmentState.MTA);
        Console.WriteLine("Try to change state: {0}", result);

        t.Start();

        Thread.Sleep(500);

        try
        {
            t.TrySetApartmentState(ApartmentState.STA);
        }
        catch (ThreadStateException)
        {
            Console.WriteLine("ThreadStateException occurs " +
                "if apartment state is set after starting thread.");
        }

        t.Join();
    }

    public static void ThreadProc()
    {
        Thread.Sleep(2000);
    }
}

/* This code example produces the following output:

Before setting apartment state: Unknown
After setting apartment state: STA
Try to change state: False
ThreadStateException occurs if apartment state is set after starting thread.
 */

open System.Threading

let threadProc () = Thread.Sleep 2000

let t = Thread threadProc
printfn $"Before setting apartment state: {t.GetApartmentState()}"

t.SetApartmentState ApartmentState.STA
printfn $"After setting apartment state: {t.GetApartmentState()}"

let result = t.TrySetApartmentState ApartmentState.MTA
printfn $"Try to change state: {result}"

t.Start()

Thread.Sleep 500

try
    t.TrySetApartmentState ApartmentState.STA |> ignore
with :? ThreadStateException ->
    printfn "ThreadStateException occurs if apartment state is set after starting thread."

t.Join()

// This code example produces the following output:
//     Before setting apartment state: Unknown
//     After setting apartment state: STA
//     Try to change state: False
//     ThreadStateException occurs if apartment state is set after starting thread.

Imports System.Threading

Module Example

    Sub Main()
 
        Dim t As New Thread(AddressOf ThreadProc)
        Console.WriteLine("Before setting apartment state: {0}", _
            t.GetApartmentState())

        t.SetApartmentState(ApartmentState.STA)
        Console.WriteLine("After setting apartment state: {0}", _
            t.GetApartmentState())

        Dim result As Boolean = _
            t.TrySetApartmentState(ApartmentState.MTA)
        Console.WriteLine("Try to change state: {0}", result)

        t.Start()

        Thread.Sleep(500)

        Try
            t.TrySetApartmentState(ApartmentState.STA)
        Catch ex As ThreadStateException
            Console.WriteLine("ThreadStateException occurs " & _
                "if apartment state is set after starting thread.")
        End Try

        t.Join()
    End Sub

    Sub ThreadProc()
        Thread.Sleep(2000)
    End Sub
End Module

' This code example produces the following output:
'
'Before setting apartment state: Unknown
'After setting apartment state: STA
'Try to change state: False
'ThreadStateException occurs if apartment state is set after starting thread.

Remarks

This method, along with the SetApartmentState method and the TrySetApartmentState method, replaces the ApartmentState property.