public CoreDispatcher()
{
_highSyncCtx = new CoreDispatcherSynchronizationContext(this, CoreDispatcherPriority.High);
_normalSyncCtx = new CoreDispatcherSynchronizationContext(this, CoreDispatcherPriority.Normal);
_lowSyncCtx = new CoreDispatcherSynchronizationContext(this, CoreDispatcherPriority.Low);
_idleSyncCtx = new CoreDispatcherSynchronizationContext(this, CoreDispatcherPriority.Idle);
_idleDispatchedHandlerArgs = new IdleDispatchedHandlerArgs(() => IsQueueIdle);
Initialize();
}
private void DispatchItems()
{
UIAsyncOperation operation = null;
CoreDispatcherPriority operationPriority = CoreDispatcherPriority.Normal;
for (int i = 3; i >= 0; i--)
{
var queue = _queues[i];
lock (_gate)
{
if (queue.Count > 0)
{
operation = queue.Dequeue();
operationPriority = (CoreDispatcherPriority)(i - 2);
if (DecrementGlobalCount() > 0)
{
EnqueueNative();
}
break;
}
}
}
if (operation != null)
{
if (!operation.IsCancelled)
{
IDisposable runActivity = null;
try
{
if (_trace.IsEnabled)
{
runActivity = _trace.WriteEventActivity(
TraceProvider.CoreDispatcher_InvokeStart,
TraceProvider.CoreDispatcher_InvokeStop,
relatedActivity: operation.ScheduleEventActivity,
payload: new[] { ((int)operationPriority).ToString(), operation.GetDiagnosticsName() }
);
}
using (runActivity)
{
using (CoreDispatcherSynchronizationContext.Apply(this, operationPriority))
{
operation.Action();
operation.Complete();
}
}
}
catch (Exception ex)
{
if (_trace.IsEnabled)
{
_trace.WriteEvent(TraceProvider.CoreDispatcher_Exception, EventOpcode.Send, new[] { ex.GetType().ToString(), operation.GetDiagnosticsName() });
}
operation.SetError(ex);
this.Log().Error("Dispatcher unhandled exception", ex);
}
}
else
{
if (_trace.IsEnabled)
{
_trace.WriteEvent(TraceProvider.CoreDispatcher_Cancelled, EventOpcode.Send, new[] { operation.GetDiagnosticsName() });
}
}
}
else
{
throw new InvalidOperationException("Dispatch queue is empty");
}
}