In the control panel of Windows there is a combobox where we can change the regional format (controlPanel => Region => Formats (windows 10)). For example Persian or English

I want to retrieve this regional setting in my application.

I tried code like this:

        CultureInfo ci = CultureInfo.InstalledUICulture;
        var installed = ci.Name;

        ci = CultureInfo.CurrentUICulture;
        var currentUi = ci.Name;

        ci = CultureInfo.CurrentCulture;
        var current = ci.Name;

but installed and currentUi are always 'en-US' and current is 'fa-IR'

and when I change the format in the control panel they don't change.