public async void ShowProgressWindow(WorkProgressViewModel workProgress, int minDelay)
{
if (workProgress == null)
{
throw new ArgumentNullException(nameof(workProgress));
}
// Tell the work progress view model that a window will be open for it
workProgress.NotifyWindowWillOpen();
// Create a container object for the work progress to put it in the queue
var progress = new PendingWorkProgress(workProgress);
// As soon as the work is finished, we should display the window, even if the delay is not complete
workProgress.WorkFinished += (sender, e) => progress.ReadyToDisplay.TrySetResult(0);
if (workProgress.WorkDone)
{
progress.ReadyToDisplay.TrySetResult(0);
}
// Compute the list of progress window that should be displayed before this one
List <PendingWorkProgress> precedingWindows;
lock (pendingProgressWindows)
{
precedingWindows = new List <PendingWorkProgress>(pendingProgressWindows);
pendingProgressWindows.Add(progress);
}
// Enqueue a task to display the window when it's ready.
DisplayProgressWindow(precedingWindows, progress);
// Wait the delay before notifying that we're ready to display
await Task.Delay(minDelay);
progress.ReadyToDisplay.TrySetResult(0);
}
private async void DisplayProgressWindow(List <PendingWorkProgress> precedingWindows, PendingWorkProgress nextWindow)
{
// Wait for all preceding windows to be displayed first
await Task.WhenAll(precedingWindows.Select(x => x.Displayed.Task));
// Then wait for the next window to be ready to display
await nextWindow.ReadyToDisplay.Task;
// Check if we should actually display the window
if (!nextWindow.WorkProgress.WorkDone || nextWindow.WorkProgress.ShouldStayOpen())
{
await nextWindow.WorkProgress.Dispatcher.InvokeAsync(() =>
{
var progressWindow = new WorkProgressWindow(nextWindow.WorkProgress);
// Remove this window from the list of pending window
lock (pendingProgressWindows)
{
pendingProgressWindows.Remove(nextWindow);
}
try
{
// Notify in the next frame that the window has been displayed
nextWindow.WorkProgress.Dispatcher.InvokeAsync(() => nextWindow.Displayed.SetResult(0));
WindowManager.ShowBlockingWindow(progressWindow);
}
catch (Exception e)
{
// On Windows 8, an exception might occur in the System.Windows.Shell.WindowChromeWorker class
// if the progress window is closed programmatically, apparently if this happens too early after
// loading it. Let's ignore the exception for the moment, as a workaround.
e.Ignore();
}
});
}
else
{
// Remove this window from the list of pending window
lock (pendingProgressWindows)
{
pendingProgressWindows.Remove(nextWindow);
}
// Notify that the window should be considered as displayed.
nextWindow.Displayed.SetResult(0);
}
nextWindow.WorkProgress.NotifyWindowClosed();
}
