通过C＃使用DateTimePicker更改系统日期和时间？

Question

I'm trying to change the time but when I try to change the time to 00:00 it becomes 08:00 instead? Is it considering my timezone which is UTC + 8?

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Runtime.InteropServices;
namespace LibraryAdmin
{
    public partial class Form41 : Form
    {
        public Form41()
        {
            InitializeComponent();
        }

        public struct SystemTime
        {
            public ushort Year;
            public ushort Month;
            public ushort DayOfWeek;
            public ushort Day;
            public ushort Hour;
            public ushort Minute;
            public ushort Second;
            public ushort Millisecond;
        };

        [DllImport("kernel32.dll", EntryPoint = "GetSystemTime", SetLastError = true)]
        public extern static void Win32GetSystemTime(ref SystemTime sysTime);

        [DllImport("kernel32.dll", EntryPoint = "SetSystemTime", SetLastError = true)]
        public extern static bool Win32SetSystemTime(ref SystemTime sysTime);

        private void Form41_Load(object sender, EventArgs e)
        {    
        }

        private void button1_Click(object sender, EventArgs e)
        {
            SystemTime updatedTime = new SystemTime();
            updatedTime.Year = (ushort)dateTimePicker1.Value.Year;
            updatedTime.Month = (ushort)dateTimePicker1.Value.Month;
            updatedTime.Day = (ushort)dateTimePicker1.Value.Day;

            updatedTime.Hour = (ushort)((dateTimePicker2.Value.Hour))  ;
            updatedTime.Minute = (ushort)dateTimePicker2.Value.Minute;
            updatedTime.Second = (ushort)dateTimePicker2.Value.Second;
            Win32SetSystemTime(ref updatedTime);
        }

        private void dateTimePicker2_ValueChanged(object sender, EventArgs e)
        {
            this.dateTimePicker2.Value.ToFileTimeUtc();
        }
    }
}

Answer 1

Yes, it's precisely because of the time zone issue. From the docs for SetSystemTime :

Sets the current system time and date. The system time is expressed in Coordinated Universal Time (UTC).

So if you're trying to change it to a particular local time, you should convert that to UTC first. For example:

private void button1_Click(object sender, EventArgs e)
{
    var local = dateTimePicker1.Value;
    var utc = local.ToUniversalTime();
    SystemTime updatedTime = new SystemTime
    {
         Year = (ushort) utc.Year,
         Month = (ushort) utc.Month,
         Day = (ushort) utc.Day,
         Hour = (ushort) utc.Hour,
         Minute = (ushort) utc.Minute,
         Second = (ushort) utc.Second,
    };
    Win32SetSystemTime(ref updatedTime);
}