C#中怎样实现把系统时间向前或者向后调啊？

Question

rtThanks a lot!!!

Answer 1

using System.Runtime.InteropServices; //imports SetLocalTime function from kernel32.dll 
[DllImport("kernel32.dll", SetLastError=true)]  
public static extern int SetLocalTime (ref SystemTime lpSystemTime); //struct for date/time apis 
public struct SystemTime 
{ 
public short wYear; 
public short wMonth; 
public short wDayOfWeek; 
public short wDay; 
public short wHour; 
public short wMinute; 
public short wSecond; 
public short wMilliseconds; 
} // And then set up a structure with the required properties and call the api from code: SystemTime systNew = new SystemTime(); // 设置属性 
systNew.wDay = 1; 
systNew.wMonth = 1; 
systNew.wYear = 2004; 
systNew.wHour = 9; 
systNew.wMinute = 0; 
systNew.wSecond = 0; // 调用API，更新系统时间 
SetLocalTime(ref systNew);

Answer 2

来自：http://www.pinvoke.net/default.aspx/kernel32/SetLocalTime.html    //I have added some methods to structure SYSTEMTIME. After that the convertion between System.DateTime and SYSTEM became much easier. :)
    //Sample Code in C#:    //Sample code for SetLocalTime and SYSTEMTIME structure
    //Author:    Yuan Xiaohui from www.farproc.com
    //Time :    August 30th, 2005    using System;
    using System.Runtime.InteropServices;    public class MyClass1
    {
        /// <summary>
        /// SYSTEMTIME structure with some useful methods
        /// </summary>
        public struct SYSTEMTIME
        {
            public ushort wYear;
            public ushort wMonth;
            public ushort wDayOfWeek;
            public ushort wDay;
            public ushort wHour;
            public ushort wMinute;
            public ushort wSecond;
            public ushort wMilliseconds;            /// <summary>
            /// Convert form System.DateTime
            /// </summary>
            /// <param name="time"></param>
            public void FromDateTime(DateTime time)
            {
                wYear = (ushort)time.Year;
                wMonth = (ushort)time.Month;
                wDayOfWeek = (ushort)time.DayOfWeek;
                wDay = (ushort)time.Day;
                wHour = (ushort)time.Hour;
                wMinute = (ushort)time.Minute;
                wSecond = (ushort)time.Second;
                wMilliseconds = (ushort)time.Millisecond;
            }            /// <summary>
            /// Convert to System.DateTime
            /// </summary>
            /// <returns></returns>
            public DateTime ToDateTime()
            {
                return new DateTime(wYear, wMonth, wDay, wHour, wMinute, wSecond, wMilliseconds);
            }
            /// <summary>
            /// STATIC: Convert to System.DateTime
            /// </summary>
            /// <param name="time"></param>
            /// <returns></returns>
            public static DateTime ToDateTime(SYSTEMTIME time)
            {
                return time.ToDateTime();
            }
        }        //SetLocalTime C# Signature
        [DllImport("Kernel32.dll")]
        public static extern bool SetLocalTime( ref SYSTEMTIME Time );        //Example
        private void Add7Days        {
            //Get current time and adds 7 days to it
            DateTime t = DateTime.Now.AddDays(7);;
            //Convert to SYSTEMTIME
            SYSTEMTIME st = new SYSTEMTIME();
            st.FromDateTime(t);
            //Call Win32 API to set time
            SetLocalTime(ref st);
        }
    }