VBA Excel - Hàm sửa ngày

Public Function SuaNgay(NgayBatKy)

' Original Design 2002

If Not IsDate(NgayBatKy) Then

MsgBox "Ngaøy khoâng hôïp leä"

SuaNgay = Date

Else

WorkString = NgayBatKy

WPosition = InStr(1, WorkString, "/")

WDD = Left(WorkString, WPosition - 1): WorkString = Mid(WorkString, WPosition + 1)

WPosition = InStr(1, WorkString, "/")

If WPosition = 0 Then

WMM = WorkString: WYY = Year(Date)

Else

WMM = Left(WorkString, WPosition - 1): WYY = Mid(WorkString, WPosition + 1)

End If

SuaNgay = DateSerial(WYY, WMM, WDD)

End If