ApartmentState Enumeration
Assembly: mscorlib (in mscorlib.dll)
An apartment is a logical container within a process for objects sharing the same thread access requirements. All objects in the same apartment can receive calls from any thread in the apartment. The .NET Framework does not use apartments, and managed objects are responsible for using all shared resources in a thread-safe manner themselves.
Because COM classes use apartments, the common language runtime needs to create and initialize an apartment when calling a COM object in a COM interop situation. A managed thread can create and enter a single-threaded apartment (STA) that allows only one thread, or a multithreaded apartment (MTA) that contains one or more threads. You can control the type of apartment created by setting the ApartmentState property of the thread to one of the values of the ApartmentState enumeration. Because a given thread can only initialize a COM apartment once, you cannot change the apartment type after the first call to the unmanaged code.
For more information, see Thread, Managed and Unmanaged Threading, and Advanced COM Interoperability.
The following code example demonstrates how to set the apartment state of a thread.
using System; using System.Threading; class ApartmentTest { static void Main() { Thread newThread = new Thread(new ThreadStart(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.ApartmentState); 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(ThreadStateException stateException) { Console.WriteLine("\n{0} caught:\n" + "Thread is not in the Unstarted or Running state.", stateException.GetType().Name); Console.WriteLine("ThreadState: {0}, ApartmentState: {1}", newThread.ThreadState, newThread.GetApartmentState()); } } static void ThreadMethod() { Thread.Sleep(1000); } }
import System.*;
import System.Threading.*;
import System.Threading.Thread;
class ApartmentTest
{
public static void main(String[] args)
{
Thread newThread = new Thread(new ThreadStart(ThreadMethod));
newThread.set_ApartmentState(ApartmentState.MTA);
// The following line is ignored since
// ApartmentState can only be set once.
newThread.set_ApartmentState(ApartmentState.STA);
Console.WriteLine("ThreadState: {0}, ApartmentState: {1}",
newThread.get_ThreadState(),
newThread.get_ApartmentState());
newThread.Start();
// Wait for newThread to start and go to sleep.
Thread.Sleep(300);
try {
// This causes an exception since newThread is sleeping.
newThread.set_ApartmentState(ApartmentState.STA);
}
catch (ThreadStateException stateException) {
Console.WriteLine("\n{0} caught:\n" +
"Thread is not in the Unstarted or Running state.",
stateException.GetType().get_Name());
Console.WriteLine("ThreadState: {0}, ApartmentState: {1}",
newThread.get_ThreadState(),newThread.get_ApartmentState());
}
} //main
static void ThreadMethod()
{
Thread.Sleep(1000);
} //ThreadMethod
} //ApartmentTest
Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.