As an UWP App runs in window mode on common desktop systems the "old" way of getting the screen resolution won't work anymore.
Old Resolution with
To improve the other answers even a bit more, the following code also takes care of scaling factors, e.g. for my 200% for my Windows display (correctly returns 3200x1800) and 300% of the Lumia 930 (1920x1080).
var bounds = ApplicationView.GetForCurrentView().VisibleBounds; var scaleFactor = DisplayInformation.GetForCurrentView().RawPixelsPerViewPixel; var size = new Size(bounds.Width*scaleFactor, bounds.Height*scaleFactor);
As stated in the other answers, this only returns the correct size on Desktop before the size of root frame is changed.