La respuesta de rix0rrr es excelente, pero no admite desplazamientos de zona horaria sin dos puntos o con solo horas. Mejoré ligeramente la función para agregar soporte para estos formatos:
Public Declare Function SystemTimeToFileTime Lib _
"kernel32" (lpSystemTime As SYSTEMTIME, _
lpFileTime As FILETIME) As Long
Public Declare Function FileTimeToLocalFileTime Lib _
"kernel32" (lpLocalFileTime As FILETIME, _
lpFileTime As FILETIME) As Long
Public Declare Function FileTimeToSystemTime Lib _
"kernel32" (lpFileTime As FILETIME, lpSystemTime _
As SYSTEMTIME) As Long
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
Public Function ISODATE(iso As String)
Dim tPos As Integer: tPos = InStr(iso, "T")
If tPos = 0 Then tPos = Len(iso) + 1
Dim zPos As Integer: zPos = InStr(iso, "Z")
If zPos = 0 Then zPos = InStr(iso, "+")
If zPos = 0 Then zPos = InStr(tPos, iso, "-")
If zPos = 0 Then zPos = Len(iso) + 1
If zPos = tPos Then zPos = tPos + 1
Dim datePart As String: datePart = Mid(iso, 1, tPos - 1)
Dim timePart As String: timePart = Mid(iso, tPos + 1, zPos - tPos - 1)
Dim dotPos As Integer: dotPos = InStr(timePart, ".")
If dotPos = 0 Then dotPos = Len(timePart) + 1
timePart = Left(timePart, dotPos - 1)
Dim d As Date: d = DateValue(datePart)
Dim t As Date: If timePart <> "" Then t = TimeValue(timePart)
Dim dt As Date: dt = d + t
Dim tz As String: tz = Mid(iso, zPos)
If tz <> "" And Left(tz, 1) <> "Z" Then
Dim colonPos As Integer: colonPos = InStr(tz, ":")
Dim minutes As Integer
If colonPos = 0 Then
If (Len(tz) = 3) Then
minutes = CInt(Mid(tz, 2)) * 60
Else
minutes = CInt(Mid(tz, 2, 5)) * 60 + CInt(Mid(tz, 4))
End If
Else
minutes = CInt(Mid(tz, 2, colonPos - 2)) * 60 + CInt(Mid(tz, colonPos + 1))
End If
If Left(tz, 1) = "+" Then minutes = -minutes
dt = DateAdd("n", minutes, dt)
End If
dt = UTCToLocalTime(dt)
ISODATE = dt
End Function
Public Function UTCToLocalTime(dteTime As Date) As Date
Dim infile As FILETIME
Dim outfile As FILETIME
Dim insys As SYSTEMTIME
Dim outsys As SYSTEMTIME
insys.wYear = CInt(Year(dteTime))
insys.wMonth = CInt(Month(dteTime))
insys.wDay = CInt(Day(dteTime))
insys.wHour = CInt(Hour(dteTime))
insys.wMinute = CInt(Minute(dteTime))
insys.wSecond = CInt(Second(dteTime))
Call SystemTimeToFileTime(insys, infile)
Call FileTimeToLocalFileTime(infile, outfile)
Call FileTimeToSystemTime(outfile, outsys)
UTCToLocalTime = CDate(outsys.wMonth & "/" & _
outsys.wDay & "/" & _
outsys.wYear & " " & _
outsys.wHour & ":" & _
outsys.wMinute & ":" & _
outsys.wSecond)
End Function
Public Sub ISODateTest()
Dim d1 As Date: d1 = ISODATE("2011-01-01")
Dim d2 As Date: d2 = ISODATE("2011-01-01T00:00:00")
Dim d3 As Date: d3 = ISODATE("2011-01-01T00:00:00Z")
Dim d4 As Date: d4 = ISODATE("2011-01-01T12:00:00Z")
Dim d5 As Date: d5 = ISODATE("2011-01-01T12:00:00+05:00")
Dim d6 As Date: d6 = ISODATE("2011-01-01T12:00:00-05:00")
Dim d7 As Date: d7 = ISODATE("2011-01-01T12:00:00.05381+05:00")
Dim d8 As Date: d8 = ISODATE("2011-01-01T12:00:00-0500")
Dim d9 As Date: d9 = ISODATE("2011-01-01T12:00:00-05")
AssertEqual "Date and midnight", d1, d2
AssertEqual "With and without Z", d2, d3
AssertEqual "With timezone", -5, DateDiff("h", d4, d5)
AssertEqual "Timezone Difference", 10, DateDiff("h", d5, d6)
AssertEqual "Ignore subsecond", d5, d7
AssertEqual "No colon in timezone offset", d5, d8
AssertEqual "No minutes in timezone offset", d5, d9
Dim w As Date: w = ISODATE("2010-02-23T21:04:48+01:00")
Dim s As Date: s = ISODATE("2010-07-23T21:04:48+01:00")
AssertEqual "Winter/Summer hours", Hour(w), Hour(s)
MsgBox "All tests passed succesfully!"
End Sub
Sub AssertEqual(name, x, y)
If x <> y Then Err.Raise 1234, Description:="Failed: " & name & ": '" & x & "' <> '" & y & "'"
End Sub
TryParseExactDate( "yyyy-MM-dd'T'HH:mm:ss", A1 )función simple en su biblioteca de fórmulas expansiva. ¿Cuál es la excusa de Microsoft? :(