c++ - Windows 8 APP，使用数据绑定(bind)更改 XAML 文本框的文本...导致问题的游戏循环工作线程

Question

我已经使用 Direct3D 使用 XAML 创建了一个新项目(所以我最后可以有广告)...

我有一个文本 block 并将其绑定(bind)到 View 模型中的属性。

<SwapChainPanel x:Name="swapChainPanel">
    <TextBlock x:Name="debugText"  HorizontalAlignment="Left" Margin="204,658,0,0" TextWrapping="Wrap" Text="{Binding Debug}" VerticalAlignment="Top" />
</SwapChainPanel>

如果我在我的 XAML.cpp 文件中，并将属性值更改为某个值，则一切正常...

this->DataContext = m_deviceResources->directXPageViewModel;

m_deviceResources->directXPageViewModel->Debug = "YUMMY";
m_deviceResources->directXPageViewModel->Update( ); // runs property changed notifier

如果我在游戏循环中更改属性，屏幕会变成空白并且不会抛出明显的错误？

// So the same code as above (without this->Datacontext) placed inside my game class.

这似乎是因为游戏类渲染循环在工作线程内:

// If the animation render loop is already running then do not start another thread.
if (m_renderLoopWorker != nullptr && m_renderLoopWorker->Status == AsyncStatus::Started)
{
    return;
}

// Create a task that will be run on a background thread.

//IF I PLACE THE CODE HERE, IT WORKS FINE
auto workItemHandler = ref new WorkItemHandler([this](IAsyncAction ^ action)
{   
    // BUT IF HERE, IT SHOWS BLACK SCREEN AND STOPS LOOPING
    m_deviceResources->directXPageViewModel->Debug = "YUMMY";
    m_deviceResources->directXPageViewModel->Update( );

    // Calculate the updated frame and render once per vertical blanking interval.
    while (action->Status == AsyncStatus::Started)
    {
        critical_section::scoped_lock lock(m_criticalSection);
        Update(); // I'D REALLY LIKE TO PUT THE CODE IN HERE
        if (Render())
        {
            m_deviceResources->Present( );
        }
    }
});

// Run task on a dedicated high priority background thread.
m_renderLoopWorker = ThreadPool::RunAsync(workItemHandler, WorkItemPriority::High, WorkItemOptions::TimeSliced);

当我需要在正确的线程中时，如何在每个循环中调用更新函数(我猜)

编辑::::::::::::::::::::::::::

我的代码现在看起来像这样

// Create a task that will be run on a background thread.
auto workItemHandler = ref new WorkItemHandler([this](IAsyncAction ^ action)
{


    // Calculate the updated frame and render once per vertical blanking interval.
    while (action->Status == AsyncStatus::Started)
    {
        critical_section::scoped_lock lock(m_criticalSection);
        Update( );


        // THIS IS THE NEW CALL BUT IT CRASHES MY GAME :)
        CoreWindow::GetForCurrentThread( )->Dispatcher->RunAsync( CoreDispatcherPriority::Normal, ref new Windows::UI::Core::DispatchedHandler( [ this ]( )
        {
            m_deviceResources->directXPageViewModel->Debug = "YUMMY";
            m_deviceResources->directXPageViewModel->Update( );
        } ) );

        if (Render())
        {
            m_deviceResources->Present( );
        }
    }
});

这有一些问题，很难找出到底发生了什么。我认为 CoreDispatcher 是 NULL 或其他东西，所以它崩溃了:

Unhandled exception at 0x00BB84C7 in Game.exe: 0xC0000005: Access violation reading location 0x00000000.

directXPageViewModel.h

Answer 1

看看 CoreDispatcher类(class)。您应该将更新 UI 的代码放在 lambda 中，然后将该 lambda 传递给调度程序的 RunAsync 方法。