C# 设置本机日期格式

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;

namespace ZB.QueueSys.Common
{
    public class SetTimeHelper
    {
        //定义一个用于保存静态变量的实例
        private static SetTimeHelper instance = null;
        //定义一个保证线程同步的标识
        private static readonly object locker = new object();
        //构造函数为私有，使外界不能创建该类的实例
        private SetTimeHelper() { }
        public static SetTimeHelper Instance
        {
            get
            {
                if (instance == null)
                {
                    lock (locker)
                    {
                        if (instance == null) instance = new SetTimeHelper();
                    }
                }
                return instance;
            }
        }

        [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;

        //[DllImport("kernel32.dll", EntryPoint = "SetLocaleInfoA")]
        //public static extern int SetLocaleInfo(int Locale, int LCType, string lpLCData);
        [DllImport("user32.dll", EntryPoint = "SendMessageTimeout")]
        public static extern long SendMessageTimeout(int hWnd, int Msg, int wParam, int lParam, int fuFlags, int uTimeout, ref int lpdwResult);
        [DllImport("User32.dll", EntryPoint = "PostMessage")]
        public static extern int PostMessage(
        int hWnd, // handle to destination window
        int Msg, // message
        int wParam, // first message parameter
        int lParam // second message parameter
        );

        public const int LOCALE_USER_DEFAULT = 0x0400;
        public const int LOCALE_SYSTEM_DEFAULT = 0x0800;
        //public const int LOCALE_SSHORTDATE = 0x1F;
        public const int LOCALE_STIMEFORMAT = 0x1003;
        public const int HWND_BROADCAST = 0xFFFF;
        public const int WM_SETTINGCHANGE = 0x001A;
        public const int SMTO_ABORTIFHUNG = 2;

        public void SetDateTimeFormat()
        {
            try
            {
                int x = GetSystemDefaultLCID();
                SetLocaleInfo(x, LOCALE_STIME, "HH:mm:ss");        //时间格式
                SetLocaleInfo(x, LOCALE_SSHORTDATE, "yyyy-MM-dd");   //短日期格式  
                SetLocaleInfo(x, LOCALE_SLONGDATE, "yyyy-MM-dd");   //长日期格式 
            }
            catch (Exception ex)
            {
                //Console.WriteLine(ex);
            }
        }

        public void SetDateTimeFormat2()
        {
            int p = 0;
            //设置短日期格式
            SetLocaleInfo(LOCALE_USER_DEFAULT, LOCALE_SSHORTDATE, "yyyy-MM-dd");
            //设置时间格式，24小时制
            SetLocaleInfo(LOCALE_USER_DEFAULT, LOCALE_STIMEFORMAT, "HH:mm:ss");
            //设置完成后必须调用，通知其他程序格式已经更改，否则即使是程序自身也不能使用新设置的格式
            SendMessageTimeout(HWND_BROADCAST, WM_SETTINGCHANGE, 0, 0, SMTO_ABORTIFHUNG, 10, ref p);
        }

        public void ConvertDateTimeFormat() 
        {
            SetDateTimeFormat();
            SetDateTimeFormat2();
        }



    }
}