Cannot convert null literal to non-nullable reference type.

'SliderView.PreviewTextInput(object, TextCompositionEventArgs)' hides inherited member 'UIElement.PreviewTextInput'. Use the new keyword if hiding was intended.

Non-nullable field 'Description' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the field as nullable.

Non-nullable field 'DeviceInstanceId' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the field as nullable.

Non-nullable field '_slideDownAnimation' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the field as nullable.

Non-nullable field '_slideDownCompleteHandler' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the field as nullable.

Nullability of reference types in type of parameter 'sender' of 'void MainWindowViewModel.OnWindowClosing(object sender, CancelEventArgs e)' doesn't match the target delegate 'CancelEventHandler' (possibly because of nullability attributes).

Non-nullable property 'Title' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the property as nullable.

Non-nullable property 'Icon' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the property as nullable.