Thread.TrySetApartmentState(ApartmentState) Metoda

Definice

Nastaví stav objektu apartment vlákna před jeho spuštěním.Sets the apartment state of a thread before it is started.

public:
 bool TrySetApartmentState(System::Threading::ApartmentState state);
public bool TrySetApartmentState (System.Threading.ApartmentState state);
member this.TrySetApartmentState : System.Threading.ApartmentState -> bool
Public Function TrySetApartmentState (state As ApartmentState) As Boolean

Parametry

state
ApartmentState

Nový stav objektu apartment.The new apartment state.

Návraty

true, pokud je nastaven stav objektu Apartment; v opačném případě false.true if the apartment state is set; otherwise, false.

Výjimky

Pouze .NET Core: Tento člen není podporován na platformách macOS a Linux..NET Core only: This member is not supported on the macOS and Linux platforms.

state není platným stavem typu apartment.state is not a valid apartment state.

Vlákno bylo spuštěno a ukončeno nebo volání není provedeno z kontextu vlákna, když je vlákno spuštěno.The thread was started and has terminated, or the call is not being made from the thread's context while the thread is running.

Příklady

Následující příklad kódu ukazuje metody GetApartmentState, SetApartmentStatea TrySetApartmentState.The following code example demonstrates the GetApartmentState, SetApartmentState, and TrySetApartmentState methods. Příklad kódu vytvoří vlákno.The code example creates a thread. Před zahájením vlákna GetApartmentState zobrazí počáteční stav ApartmentState.Unknown a SetApartmentState změní stav na ApartmentState.STA.Before the thread is started, GetApartmentState displays the initial ApartmentState.Unknown state and SetApartmentState changes the state to ApartmentState.STA. Metoda TrySetApartmentState pak vrátí false při pokusu o změnu stavu na ApartmentState.MTA, protože stav objektu Apartment již je nastaven.The TrySetApartmentState method then returns false when attempting to change the state to ApartmentState.MTA because the apartment state is already set. Pokud došlo k pokusu o provedení stejné operace s SetApartmentState, InvalidOperationException by byl vyvolán.If the same operation had been attempted with SetApartmentState, InvalidOperationException would have been thrown.

Po spuštění vlákna se znovu použije metoda TrySetApartmentState.After the thread is started, the TrySetApartmentState method is used again. Tentokrát to vyvolá ThreadStateException, protože vlákno již bylo spuštěno.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.
 */
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.

Poznámky

Nová vlákna jsou inicializována jako ApartmentState.MTA, pokud jejich stav objektu Apartment nebyl nastaven před jejich spuštěním.New threads are initialized as ApartmentState.MTA if their apartment state has not been set before they are started. Před spuštěním vlákna musí být nastaven stav bytu.Apartment state must be set before a thread is started.

Poznámka

Hlavní vlákno aplikace je inicializováno jako ApartmentState.MTA ve výchozím nastavení.The main application thread is initialized to ApartmentState.MTA by default. Jediným způsobem, jak nastavit stav objektu Apartment hlavního vlákna aplikace na ApartmentState.STA, je použít atribut STAThreadAttribute na metodu vstupního bodu.The only way to set the apartment state of the main application thread to ApartmentState.STA is to apply the STAThreadAttribute attribute to the entry point method.

Metoda TrySetApartmentState společně s metodou GetApartmentState a metodou SetApartmentState nahrazuje vlastnost ApartmentState.The TrySetApartmentState method, along with the GetApartmentState method and the SetApartmentState method, replaces the ApartmentState property.

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