DispatcherQueue.ShutdownStarting Event

Definition

Namespace:

Microsoft.UI.Dispatching

Raised when either ShutdownQueue or ShutdownQueueAsync is called. For a full list of the events raised, and in what order, see the Remarks for ShutdownQueueAsync.

// Register
event_token ShutdownStarting(TypedEventHandler<DispatcherQueue, DispatcherQueueShutdownStartingEventArgs const&> const& handler) const;

// Revoke with event_token
void ShutdownStarting(event_token const* cookie) const;

// Revoke with event_revoker
DispatcherQueue::ShutdownStarting_revoker ShutdownStarting(auto_revoke_t, TypedEventHandler<DispatcherQueue, DispatcherQueueShutdownStartingEventArgs const&> const& handler) const;

public event TypedEventHandler<DispatcherQueue,DispatcherQueueShutdownStartingEventArgs> ShutdownStarting;

function onShutdownStarting(eventArgs) { /* Your code */ }
dispatcherQueue.addEventListener("shutdownstarting", onShutdownStarting);
dispatcherQueue.removeEventListener("shutdownstarting", onShutdownStarting);
- or -
dispatcherQueue.onshutdownstarting = onShutdownStarting;

Public Custom Event ShutdownStarting As TypedEventHandler(Of DispatcherQueue, DispatcherQueueShutdownStartingEventArgs) 

Event Type

TypedEventHandler<DispatcherQueue,DispatcherQueueShutdownStartingEventArgs>

Examples

_dispatcherQueue.ShutdownStarting += (s, e) =>
{
    // Queue is shutting down, do this last operation to  
    // update state before the dispatcher loop exits
    _queue.TryEnqueue(
        () =>
        {
            // clean up state
        });
};

Remarks

The ShutdownStarting event is raised from the event loop thread before the event loop exits. The handler for this event can take a deferral, and can continue to post work until the deferral completes. Once the deferral completes, the DispatcherQueue no longer accepts work, and DispatcherQueue.TryEnqueue returns false.