如何设置系统时间？

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Runtime.InteropServices;namespace Example105_设置系统时间
{
/// <summary>
/// Form1 的摘要说明。
/// </summary>
public class Form1 : System.Windows.Forms.Form
{
private System.Windows.Forms.Timer timer1;
private System.Windows.Forms.DateTimePicker dateTimePicker1;
private System.Windows.Forms.Button button1;
private System.ComponentModel.IContainer components; public Form1()
{
//
// Windows 窗体设计器支持所必需的
//
InitializeComponent(); //
// TODO: 在 InitializeComponent 调用后添加任何构造函数代码
//
} /// <summary>
/// 清理所有正在使用的资源。
/// </summary>
protected override void Dispose( bool disposing )
{
if( disposing )
{
if (components != null) 
{
components.Dispose();
}
}
base.Dispose( disposing );
} #region Windows Form Designer generated code
/// <summary>
/// 设计器支持所需的方法 - 不要使用代码编辑器修改
/// 此方法的内容。
/// </summary>
private void InitializeComponent()
{
this.components = new System.ComponentModel.Container();
this.timer1 = new System.Windows.Forms.Timer(this.components);
this.dateTimePicker1 = new System.Windows.Forms.DateTimePicker();
this.button1 = new System.Windows.Forms.Button();
this.SuspendLayout();
// 
// timer1
// 
this.timer1.Tick += new System.EventHandler(this.timer1_Tick);
// 
// dateTimePicker1
// 
this.dateTimePicker1.Format = System.Windows.Forms.DateTimePickerFormat.Time;
this.dateTimePicker1.Location = new System.Drawing.Point(16, 24);
this.dateTimePicker1.Name = "dateTimePicker1";
this.dateTimePicker1.Size = new System.Drawing.Size(96, 21);
this.dateTimePicker1.TabIndex = 0;
// 
// button1
// 
this.button1.Location = new System.Drawing.Point(16, 56);
this.button1.Name = "button1";
this.button1.Size = new System.Drawing.Size(96, 23);
this.button1.TabIndex = 1;
this.button1.Text = "SetSystemTime";
this.button1.Click += new System.EventHandler(this.button1_Click);
// 
// Form1
// 
this.AutoScaleBaseSize = new System.Drawing.Size(6, 14);
this.ClientSize = new System.Drawing.Size(128, 93);
this.Controls.AddRange(new System.Windows.Forms.Control[] {
  this.button1,
  this.dateTimePicker1});
this.Name = "Form1";
this.Text = "Form1";
this.Load += new System.EventHandler(this.Form1_Load);
this.ResumeLayout(false); }
#endregion /// <summary>
/// 应用程序的主入口点。
/// </summary>
[STAThread]
static void Main() 
{
Application.Run(new Form1());
} [DllImport( "Kernel32.dll" )]
public static extern void GetLocalTime(SystemTime st );
[DllImport( "Kernel32.dll" )]
public static extern void SetLocalTime(SystemTime st ); [StructLayout( LayoutKind.Sequential)]
public class 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; 
} private void timer1_Tick(object sender, System.EventArgs e)
{
SystemTime st = new SystemTime();
GetLocalTime(st);
this.Text="The Date and Time is: " ;
this.Text=this.Text+st.wHour.ToString()+":";
this.Text=this.Text+st.wMinute.ToString()+":";
this.Text=this.Text+st.wSecond.ToString()+".";
this.Text=this.Text+st.wMilliseconds.ToString();
} private void Form1_Load(object sender, System.EventArgs e)
{
this.timer1.Interval=100;
this.timer1.Enabled=true;
this.dateTimePicker1.Value=DateTime.Now;
} private void button1_Click(object sender, System.EventArgs e)
{
SystemTime st = new SystemTime();
st.wYear=(ushort)this.dateTimePicker1.Value.Year;
st.wMonth=(ushort)this.dateTimePicker1.Value.Month;
st.wDay=(ushort)this.dateTimePicker1.Value.Day;
st.wHour=(ushort)this.dateTimePicker1.Value.Hour;
st.wMinute=(ushort)this.dateTimePicker1.Value.Minute;
st.wSecond=(ushort)this.dateTimePicker1.Value.Second;
SetLocalTime(st);
}
}
}