ui::WindowRef¶
Header: winui/ui/WindowRef.hpp.
A weak handle to a Window, for a worker that may outlive it. Take it with Window::ref() while the Window is known to exist (on the UI thread, before the work starts); post() through it is safe from any thread at any time, also after the Window was destroyed: the work is dropped then.
It names one Window, not an address. A new Window built where a destroyed one was (a dialog in a re-created std::optional<ui::Window>) is a different window, and work posted through a handle to the old one is dropped instead of reaching the new one. Copyable and cheap: an address and a serial number, compared but never dereferenced. A default-constructed one names no window.
Example:
// `preview` lives as long as the window, so the posted work may write it.
void load_preview(const std::filesystem::path& path, ui::Property<ui::Bitmap>& preview)
{
std::thread([home = window.ref(), path, &preview] {
ui::Bitmap image = ui::Bitmap::read_png(path);
home.post([&preview, image = std::move(image)]() mutable { preview.set(std::move(image)); });
}).detach();
}
WindowRef¶
Names no window: post() drops everything.
post¶
Window::post() through the handle: queues work for the window's next tick() and returns true, or, when that window is closed or destroyed, destroys work without running it and returns false. Callable from any thread. Dropped work is destroyed on the calling thread once no lock is held, so its destructor may post again.
get¶
The Window while it exists, null once it was destroyed (or for a default-constructed handle). On the window's own thread only: anywhere else the window may be gone by the time the pointer is used.