VBA當地時區調整

Question

假設我有本地太平洋時間（UTC-8）Excel值。例如41656.67297是17 January 2014 4:09 PM。我無法控制這個值。

我想調整相對於用戶本地時間的給定值。比如說，都柏林的某個人正在使用Excel工作簿。我想調整給定的數字並在當地時間18 January 2014 12:09 AM中顯示。是否有任何內置的Excel功能可以使這種流暢？

Answer 1

VBA本身不提供此選項，但有一個Windows API可讓您執行所需的操作。 This article描述如何操作，here是GetTimeZoneInformation上的MSDN頁面。

從CPearson頁面，使這些聲明第一：

Option Explicit 

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 


'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' 
' NOTE: If you are using the Windows WinAPI Viewer Add-In to get 
' function declarations, not that there is an error in the 
' TIME_ZONE_INFORMATION structure. It defines StandardName and 
' DaylightName As 32. This is fine if you have an Option Base 
' directive to set the lower bound of arrays to 1. However, if 
' your Option Base directive is set to 0 or you have no 
' Option Base diretive, the code won't work. Instead, 
' change the (32) to (0 To 31). 
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' 

Private Type TIME_ZONE_INFORMATION 
    Bias As Long 
    StandardName(0 To 31) As Integer 
    StandardDate As SYSTEMTIME 
    StandardBias As Long 
    DaylightName(0 TO 31) As Integer 
    DaylightDate As SYSTEMTIME 
    DaylightBias As Long 
End Type 


'''''''''''''''''''''''''''''''''''''''''''''' 
' These give symbolic names to the time zone 
' values returned by GetTimeZoneInformation . 
'''''''''''''''''''''''''''''''''''''''''''''' 

Private Enum TIME_ZONE 
    TIME_ZONE_ID_INVALID = 0  ' Cannot determine DST 
    TIME_ZONE_STANDARD = 1   ' Standard Time, not Daylight 
    TIME_ZONE_DAYLIGHT = 2   ' Daylight Time, not Standard 
End Enum 


Private Declare Function GetTimeZoneInformation Lib "kernel32" _ 
    (lpTimeZoneInformation As TIME_ZONE_INFORMATION) As Long 

Private Declare Sub GetSystemTime Lib "kernel32" _ 
    (lpSystemTime As SYSTEMTIME) 

那麼這個函數會發現用戶的本地時間和GMT偏移：

Function LocalOffsetFromGMT(Optional AsHours As Boolean = False, _ 
    Optional AdjustForDST As Boolean = False) As Double 
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' 
' LocalOffsetFromGMT 
' This returns the amount of time in minutes (if AsHours is omitted or 
' false) or hours (if AsHours is True) that should be *added* to the 
' local time to get GMT. If AdjustForDST is missing or false, 
' the unmodified difference is returned. (e.g., Kansas City to London 
' is 6 hours normally, 5 hours during DST. If AdjustForDST is False, 
' the resultif 6 hours. If AdjustForDST is True, the result is 5 hours 
' if DST is in effect.) 
' Note that the return type of the function is a Double not a Long. This 
' is to accomodate those few places in the world where the GMT offset 
' is not an even hour, such as Newfoundland, Canada, where the offset is 
' on a half-hour displacement. 
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' 

Dim TBias As Long 
Dim TZI As TIME_ZONE_INFORMATION 
Dim DST As TIME_ZONE 
DST = GetTimeZoneInformation(TZI) 

If DST = TIME_ZONE_DAYLIGHT Then 
    If AdjustForDST = True Then 
     TBias = TZI.Bias + TZI.DaylightBias 
    Else 
     TBias = TZI.Bias 
    End If 
Else 
    TBias = TZI.Bias 
End If 
If AsHours = True Then 
    TBias = TBias/60 
End If 

LocalOffsetFromGMT = TBias 

End Function 

您可以測試代碼：

MsgBox (LocalOffsetFromGMT()) 

然後將此偏移量添加到原始時間，您可以執行以下操作：

OriginalTime + TIME(LocalOffsetFromGMT(True, True), 0, 0)