System Time to File Time

[KamiKazeKiwi3]

I am trying to reset a file's times to some date during the year 1980, converting system time to file time. The only problem is that I have problems setting up correct values in the variable so the API works. Someone help me please.

'The API:

Declare Function SystemTimeToFileTime Lib "kernel32"_
Alias "SystemTimeToFileTime" (lpSystemTime As SYSTEMTIME, _
lpFileTime As FILETIME) As Long

'The datatypes:

Public Type FILETIME
dwLowDateTime As Long
dwHighDateTime As Long
End Type

Public 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

'For more information go to
'http://www.allapi.net/api/SystemTimeToFileTime.php

[Matthew Gates]

See if this example from the API-Guide helps any.

'This project needs a Common Dialog box, named CDBox.
'  (To add the Common Dialog Box to your tools menu, go to Project->Components (or press CTRL-T)
'   and select Microsoft Common Dialog control)
 
Private Declare Function CreateFile Lib "kernel32" _
Alias "CreateFileA" (ByVal lpFileName As String, ByVal _
dwDesiredAccess As Long, ByVal dwShareMode As Long, ByVal _
lpSecurityAttributes As Long, ByVal dwCreationDisposition As _
Long, ByVal dwFlagsAndAttributes As Long, ByVal hTemplateFile _
As Long) As Long
 
Private Declare Function SetFileTime Lib "kernel32" (ByVal hFile As _
Long, lpCreationTime As FILETIME, lpLastAccessTime As FILETIME, _
lpLastWriteTime As FILETIME) As Long
 
Private Declare Function SystemTimeToFileTime Lib "kernel32" _
(lpSystemTime As SYSTEMTIME, lpFileTime As FILETIME) As Long
 
Private Declare Function CloseHandle Lib "kernel32" (ByVal _
hObject As Long) As Long
 
Private Declare Function LocalFileTimeToFileTime Lib "kernel32" _
(lpLocalFileTime As FILETIME, lpFileTime As FILETIME) As Long
 
Private Type FILETIME
    dwLowDateTime As Long
    dwHighDateTime As Long
End Type
 
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 Const GENERIC_WRITE = &H40000000
Private Const OPEN_EXISTING = 3
Private Const FILE_SHARE_READ = &H1
Private Const FILE_SHARE_WRITE = &H2
 
 
Private Sub Form_Load()
    'KPD-Team 1998
    'URL: [url]http://www.allapi.net/[/url]
    '[email protected]
    Dim m_Date As Date, lngHandle As Long
    Dim udtFileTime As FILETIME
    Dim udtLocalTime As FILETIME
    Dim udtSystemTime As SYSTEMTIME
    m_Date = Format(Now, "DD-MM-YY")
 
    'Set the dialog's title
    CDBox.DialogTitle = "Choose a file ..."
    'Set the dialog's filter
    CDBox.Filter = "All Files (*.*)|*.*"
    'Show the 'Open File'-dialog
    CDBox.ShowOpen
 
    udtSystemTime.wYear = Year(m_Date)
    udtSystemTime.wMonth = Month(m_Date)
    udtSystemTime.wDay = Day(m_Date)
    udtSystemTime.wDayOfWeek = WeekDay(m_Date) - 1
    udtSystemTime.wHour = Hour(m_Date)
    udtSystemTime.wSecond = Second(m_Date)
    udtSystemTime.wMilliseconds = 0
 
    ' convert system time to local time
    SystemTimeToFileTime udtSystemTime, udtLocalTime
    ' convert local time to GMT
    LocalFileTimeToFileTime udtLocalTime, udtFileTime
    ' open the file to get the filehandle
    lngHandle = CreateFile(CDBox.Filename, GENERIC_WRITE, FILE_SHARE_READ Or FILE_SHARE_WRITE, ByVal 0&, OPEN_EXISTING, 0, 0)
    ' change date/time property of the file
    SetFileTime lngHandle, udtFileTime, udtFileTime, udtFileTime
    ' close the handle
    CloseHandle lngHandle
    MsgBox "The date of the file '" & CDBox.Filename & "' has been changed to" + Str$(m_Date), vbInformation + vbOKOnly, App.Title
End Sub

[KamiKazeKiwi3]

Sorry Mathew, it won't work. I'm tyring to set the date to a specific date, not a variable date equal to the current time. Your example wouldn't get an error, but I need to set the file time to a specific date.

[jim mcnamara]

Try

Private Type FILETIME
    dwLowDateTime As Long
    dwHighDateTime As Long
End Type

Dim myTime as FILETIME
const durationDay = 7.15828
const year = 365.24

Function SubDays(hiLong as long, years as long) as long
       Dim i as long
       i = hiLong - Clng( Cdbl(years) * year * durationDay)
       SubDays = i

End Function

Usage: assuming you have a file with this year's date
get FILETIME for the file in question
years = 2001 - 1980
myTime.dwHighDateTime = SubDays(dwHighDateTime, years)

Use myTime in SetFileTime



PS: the day const may be 3.57194 instead of 7.1....
I don't have my notes on this and I can't remember. It's one or the other. Try and see.

Als go here for more information on date arithmetic on files.