.NumberFormat sometimes returns the wrong value with dates and times

Question

It seems that every week or so someone posts a question about dates being converted (corrupted?) to American format. Like many others, I have attempted to help but the prob

Answer 1

BTW 1: It's been almost 30 years since I was in the military... I worked on helicopters and I was taught to use a format such as this in the aircraft logbooks: 3 Apr 12. So, that's how I still write dates. This way, there's no wondering about 4/3/2012 - is it April 3 or March 4?

Answer 2

I have mainly come up against formatting and date issues when opening text files which have been saved with different regional settings. Two useful cell properties for dealing with this are:

• .Text returns the cell value as it is displayed
• .Value2 returns the unformatted cell value or date serial number.

As you say, standard date and number formats depend on windows regional settings and this may not be desired behavior as the same workbook can display differently in different regions. MS introduced the regional code prefixes in number formats (circa Excel 2000?) which enforce consistent display if needed but they need to be explicitly selected.

If you really want to see a date or number as the user entered it, you could extract the contents of the .xlsx file looking at the worksheet cell format and the shared strings xml definitions which list the number formats in the saved workbook. I don't really see a need to do this though as the underlying value is stored internally as a serial number and this will not change.

Answer 3

I hacked this: I rewrite the original data in a known format. it relies on DateSerial and TimeSerial:

'Google spreadsheet stores dates in USA format (MM/DD/YYYY).  We're in Australia, using DD/MM/YYYY, so we need to swap them.
                    '
                        With dc 'the cell who contains a date in USA format.
                             d = .Value      'capture value in USA format
                             t = TimeValue(d)
                             .NumberFormat = "dd/mm/yyyy" 'set to OZ format, so Excel knows the values were swapped in its internal math.
                             .Value = DateSerial(Year(d), Month(d), Day(d)) 'DateSerial takes y,d,m. We swap Month and Day components, to get OZ format dates
                             .Value = .Value + TimeSerial(Hour(t), Minute(t), Second(t))
                             dc.Font.Bold = True                         ' We bold the cells that are swapped, for debugging
                         End With
                    End If