你能告诉我为什么下面的代码无效吗？ [英] Can you tell me why following code not working?

问题描述

  Imports  System.Runtime.InteropServices 
 
  Public  类 Form1 
 
 ' 用于传递给P / Invoke的系统时间结构......  
 
< structlayoutattribute（layoutkind.sequential）> _ 
 私有 结构 SYSTEMTIME 
 
 公共年作为 短 
 
 公开月作为 短 
 
 公开 dayOfWeek 作为 短 
 
 公共天作为 简短 
 
 公共小时作为 短 
 
 公共分钟作为 短 
 
 公共第二作为 短 
 
 < span class =code-keyword>公共毫秒作为 短 
 
 结束 结构 
 
 '  P / Invoke dec用于设置系统时间......  
 
< dllimport（  kernel32.dll）> _ 
 私有 共享 功能 SetLocalTime（ ByRef  time  As  SYSTEMTIME） As  布尔 
 
 结束 功能 
 
 公共 功能 SetDeviceTime（ ByVal  p_NewDate 作为 日期）
 
 ' 填充结构...  
 
  ' 替换< your date =object =>通过GPRS返回日期对象...  
 
  Dim  st  As  SYSTEMTIME 
 
 st.year = p_NewDate.Year 
 
 st.month = p_NewDate.Month 
 
 st.dayOfWeek = p_NewDate.DayOfWeek 
 
 st.day = p_NewDate.Day 
 
 st.hour = p_NewDate.Hour 
 
 st.minute = p_NewDate.Minute 
 
 st.second = p_NewDate.Second 
 
 st.milliseconds = p_NewDate.Millisecond 
 
 ' 设置新时间......  
 
 SetLocalTime（st）
 
 ' 返回SetLocalTime（st） 
 
 结束 函数 
 
 私有  Sub  Button1_Cl ick（ ByVal  sender  As  System。 Object  ， ByVal  e  As  System.EventArgs） Handles  Button1.Click 
 
 SetDeviceTime（  01/01/2010） 
 
 结束  Sub  
 
 结束 类 

解决方案

您需要扩展权限才能更改系统时间，请参阅 https： //msdn.microsoft.com/en-us/library/windows/desktop/ms724936(v=vs.85).aspx [ ^ ]。

Imports System.Runtime.InteropServices

Public Class Form1

    'System time structure used to pass to P/Invoke...

    <structlayoutattribute(layoutkind.sequential)> _
    Private Structure SYSTEMTIME

        Public year As Short

        Public month As Short

        Public dayOfWeek As Short

        Public day As Short

        Public hour As Short

        Public minute As Short

        Public second As Short

        Public milliseconds As Short

    End Structure

    'P/Invoke dec for setting the system time...

    <dllimport("kernel32.dll")> _
    Private Shared Function SetLocalTime(ByRef time As SYSTEMTIME) As Boolean

    End Function

    Public Function SetDeviceTime(ByVal p_NewDate As Date)

        'Populate structure...

        'Substitute <your date="" object=""> with your date object returned via GPRS...

        Dim st As SYSTEMTIME

        st.year = p_NewDate.Year

        st.month = p_NewDate.Month

        st.dayOfWeek = p_NewDate.DayOfWeek

        st.day = p_NewDate.Day

        st.hour = p_NewDate.Hour

        st.minute = p_NewDate.Minute

        st.second = p_NewDate.Second

        st.milliseconds = p_NewDate.Millisecond

        'Set the new time...

        SetLocalTime(st)

        'Return SetLocalTime(st)

    End Function

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        SetDeviceTime("01/01/2010")

    End Sub

End Class

解决方案

You need extended privileges to change the system time, see https://msdn.microsoft.com/en-us/library/windows/desktop/ms724936(v=vs.85).aspx[^].

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