public static NumberFormatInfo ReadOnly(NumberFormatInfo nfi)
{
if (nfi == null)
{
throw new ArgumentNullException(nameof(nfi));
}
if (nfi.IsReadOnly)
{
return(nfi);
}
NumberFormatInfo info = (NumberFormatInfo)(nfi.MemberwiseClone());
info.isReadOnly = true;
return(info);
}