如何保证程序运行时系统时间不被修改!

王朝vb·作者佚名  2006-01-08
窄屏简体版  字體: |||超大  

当任何程序或用户修改系统时间的时候,系统会将 WM_TIMECHANGE 消息到所有的进程,我们的程序可以捕获到该消息,然后将系统时间恢复到修改前的状态,这样就可以在我们的程序运行时系统时间的正确性,代码如下:

'窗体form1(需要一个timer控件,interval=1000):

Private Sub Form_Load()

Timer1_Timer

RegisterWindow Me.hwnd '为窗口设置子类

End Sub

Private Sub Form_Unload(Cancel As Integer)

unRegisterWindow Me.hwnd '取消窗口的子类

End Sub

Private Sub Timer1_Timer()

OldTime = Now

End Sub

'模块modle1:

Option Explicit

Public Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long

Public Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long

Public Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long

Public Declare Function CallWindowProc Lib "user32" Alias "CallWindowProcA" (ByVal lpPrevWndFunc As Long, ByVal hwnd As Long, ByVal msg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long

Public Declare Function RegisterWindowMessage Lib "user32" Alias "RegisterWindowMessageA" (ByVal lpString As String) As Long

Public OldTime As String

Public ChangeFlag As Boolean

Public Const WM_TIMECHANGE As Long = &H1E '当系统的时间变化时发送此消息给所有顶级窗口

Public oldproc As Long

Private Type SYSTEMTIME

wYear As Integer

wMonth As Integer

wDayOfWeek As Integer

wDay As Integer

wHour As Integer

wMinute As Integer

wSecond As Integer

wMilliseconds As Integer

End Type

Private Declare Function SetLocalTime Lib "kernel32" (lpSystemTime As SYSTEMTIME) As Long

Public Function RegisterWindow(hwnd As Long) As Long

If hwnd <> 0 Then

oldproc = SetWindowLong(hwnd, -4, AddressOf WinProc)

End If

End Function

Public Function unRegisterWindow(hwnd As Long) As Long

If hwnd <> 0 Then

SetWindowLong hwnd, -4, oldproc

End If

End Function

Public Function WinProc(ByVal hwnd As Long, ByVal msg As Long, ByVal lpara As Long, ByVal wpara As Long) As Long

Dim i, mytt

If msg = WM_TIMECHANGE And ChangeFlag = False Then '系统时间被修改了而且不是本程序修改的

ChangeFlag = True '本程序要修改系统时间

Call SetToOldTime '修改系统时间

Exit Function

End If

ChangeFlag = False

WinProc = CallWindowProc(oldproc, hwnd, msg, lpara, wpara)

End Function

Public Function SetToOldTime() As String '将时间恢复到设置前的状态

Dim tmp As String

tmp = OldTime '从保存的时间中取出修改前的系统时间

Dim lpSystemTime As SYSTEMTIME

lpSystemTime.wYear = Year(tmp) '取出年份

lpSystemTime.wMonth = Month(tmp) '取出月份

lpSystemTime.wDayOfWeek = -1

lpSystemTime.wDay = Day(tmp) '取出日

lpSystemTime.wHour = Hour(tmp) '取出小时

lpSystemTime.wMinute = Minute(tmp) '取出分钟

lpSystemTime.wSecond = Second(tmp) '取出秒

lpSystemTime.wMilliseconds = 0

'set the new time

SetLocalTime lpSystemTime

End Function

'到此程序就完成了,运行一下试试

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