WPF DataTrigger doesn't work.
问题 I designed a WPF Page and it should be possible to change the theme (dark theme and light theme). I am a newbie in WPF and found a solution to my problem using DataTrigger, but it don't works. 3 hours later I tried like 10 different solutions/tutorials but I don't know what I am doing wrong... The xml code: <Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:mc="http://schemas.openxmlformats.org/markup