C# How to set system date format

[DllImport("", EntryPoint = "GetSystemDefaultLCID")]
        public static extern int GetSystemDefaultLCID();
        [DllImport("", EntryPoint = "SetLocaleInfoA")]
        public static extern int SetLocaleInfo(int Locale, int LCType, string lpLCData);
        public const int LOCALE_SLONGDATE = 0x20;
        public const int LOCALE_SSHORTDATE = 0x1F;
        public const int LOCALE_STIME = 0x1003;

        public void SetDateTimeFormat()
        {
            try
            {
                int x = GetSystemDefaultLCID();
SetLocaleInfo(x, LOCALE_STIME, "HH:mm:ss");         //Time format
SetLocaleInfo(x, LOCALE_SSHORTDATE, "yyyy-MM-dd");   //Short date format
SetLocaleInfo(x, LOCALE_SLONGDATE, "yyyy-MM-dd");   //Long date format
            }
            catch (Exception ex)
            {
                (ex);
            }
        }