[DllImport("kernel32.dll", EntryPoint = "GetSystemDefaultLCID")]
        public static extern int GetSystemDefaultLCID();
        [DllImport("kernel32.dll", 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");        //時間格式 
                SetLocaleInfo(x, LOCALE_SSHORTDATE, "yyyy-MM-dd");   //短日期格式   
                SetLocaleInfo(x, LOCALE_SLONGDATE, "yyyy-MM-dd");   //長日期格式  
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex);
            }
        }