How can a universal windows app have multiple independent windows (Like Microsoft's app “Photos”)?

Question

I do know how to open additional windows using TryShowAsStandaloneAsync. However, if the original window is closed - TryShowAsStandaloneAsync fails (Wh

Answer 1

Answering why TryShowAsStandaloneAsync fails once you have closed the main window:

I think TryShowAsStandaloneAsync tries to use the main view as the anchor view (ie, a window to place the new window relative to).

Once you close the main window TryShowAsStandaloneAsync fails because it has no anchor view.

The workaround is to specify an anchorViewId of a view that is open (one of the new windows you opened prior to closing the main window), via an overload of TryShowAsStandaloneAsync:

await ApplicationViewSwitcher.TryShowAsStandaloneAsync(
    viewIdToShow, // Id of a new view, or of your hidden main view
    ViewSizePreference.Default,
    anchorViewId, // Id of one of your visible windows
    ViewSizePreference.Default);

From this answer.