出现这个错误是因为 app.xaml 的生成是 ApplicationDefinition ,所以可以右击项目的 app.xaml 文件,在属性生成选择 page 这个
✅ After March 2024 Update - I'm getting "class not registered" and sfc /scannow and DISM...:After March 2024 Update - I'm getting "class not registered" and sfc /scannow and DISM cannot fix it...