Tip 195: Modifying a File's Date and Time Stamp in Visual Basic 4.0

December 5, 1995

Abstract
In a Microsoft? Visual Basic? version 4.0 application, you may need to
modify the date and time stamp of a file. This article explains how this
can be accomplished.

Setting a New Date and Time Stamp for a File
To modify a file's date and time stamp in a Microsoft? Visual Basic?
version 4.0 application, you must perform several steps. First, you need
to call the Microsoft Windows? messaging application programming interface
(MAPI) SystemTimeToFileTime function. This function converts a system time
to a file time. The system time you want to convert must be stored in a
SYSTEMTIME structure. The converted time is then stored in a FILETIME
structure.

Next, you must use the Windows MAPI LocalFileTimeToFileTime function. This
function converts, as its name suggests, a local file time to a time that
is based on the Coordinated Universal Time (UTC). This newly converted
time information can then be used in your application by the Windows MAPI
SetFileTimeWrite function.

You must retrieve a handle to the file whose date and time stamp you want
to modify. This can be done by calling the Windows MAPI CreateFile
function. When you have the file's handle, a call to the SetFileTimeWrite
function actually updates the date and time stamp of the file.

Example Program
This program shows how to modify the date and time stamp of a file.

 1. Create a new project in Visual Basic. Form1 is created by default.
 2. Add the following code to the General Declarations section of Form1
    (note that each Declare statement must be typed as a single line of
    code):

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 Declare Function SetFileTimeWrite Lib "kernel32" Alias
   "SetFileTime" (ByVal hFile As Long, ByVal MullP As Long,
   ByVal NullP2 As Long, lpLastWriteTime As FILETIME) As Long
Private Declare Function SystemTimeToFileTime Lib "kernel32"
   (lpSystemTime As SYSTEMTIME, lpFileTime As FILETIME) As Long
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 CloseHandle Lib "kernel32" (ByVal hObject As Long)
   As Long
Private Declare Function LocalFileTimeToFileTime Lib "kernel32"
   (lpLocalFileTime As FILETIME, lpFileTime As FILETIME) As Long

 3. Add a Command Button control to Form1. Command1 is created by default.
 4. Add the following code to the Click event for Command1:

Private Sub Command1_Click()
    Dim Year As Integer, Month As Integer
    Dim Day As Integer, Hour As Integer
    Dim Minute As Integer, Second As Integer
    Dim TimeStamp As Variant
    Dim Filename As String
    Dim X As Integer

    Year = 1996
    Month = 1
    Day = 1
    Hour = 1
    Minute = 0
    Second = 0

    TimeStamp = DateSerial(Year, Month, Day) + TimeSerial(Hour, Minute, Second)
    Filename = "c:\autoexec.bat"

    X = ModifyFileStamp(Filename, TimeStamp)
    MsgBox "The time and date stamp was updated"
End Sub

 5. Create a new function called ModifyFileStamp. Add the following code
    to this function:

Function ModifyFileStamp(Filename As String, TimeStamp As Variant)
   As Integer
    Dim X As Long
    Dim Handle As Long
    Dim System_Time As SYSTEMTIME
    Dim File_Time As FILETIME
    Dim Local_Time As FILETIME

    System_Time.wYear = Year(TimeStamp)
    System_Time.wMonth = Month(TimeStamp)
    System_Time.wDay = Day(TimeStamp)
    System_Time.wDayOfWeek = WeekDay(TimeStamp) - 1
    System_Time.wHour = Hour(TimeStamp)
    System_Time.wSecond = Second(TimeStamp)
    System_Time.wMilliseconds = 0

    'convert the system time to a file time
    X = SystemTimeToFileTime(System_Time, Local_Time)

    'convert local file time to file time based on UTC
    X = LocalFileTimeToFileTime(Local_Time, File_Time)

    'open the file so we can get a file handle to the file
    Handle = CreateFile(Filename, GENERIC_WRITE, FILE_SHARE_READ Or
        FILE_SHARE_WRITE, ByVal 0&, OPEN_EXISTING, 0, 0)

    'now change the file time and date stamp
    X = SetFileTimeWrite(Handle, ByVal 0&, ByVal 0&, File_Time)
    CloseHandle Handle
End Function

Run the example program by pressing F5. Click the Command Button control.
The date and time stamp of the AUTOEXEC.BAT file is immediately updated.

Additional References
"File Times." (Library, Product Documentation, SDKs, Win32 SDK,
   Win32 Programmer's Reference, Overviews, Window Management,
   System Services, Time, About Time)
"LocalFileTimeToFileTime QuickInfo Overview Group." (Library,
   Product Documentation, SDKs, Win32 SDK, Win32 Programmer's Reference,
   Reference, Functions, LoadAccelerators to LZInit)
"SetFileTime QuickInfo Overview Group." (Library,
   Product Documentation, SDKs, Win32 SDK, Win32 Programmer's Reference,
   Reference, Functions, SetBrushOrgEx to SetGraphicsMode)
"SystemTimeToFileTime QuickInfo Overview Group." (Library,
   Product Documentation, SDKs, Win32 SDK, Win32 Programmer's Reference,
   Reference, Functions, ShowCursor to UnhandledExceptionFilter)