# When To Use ActiveWorkbook and ThisWorkbook
It's a VBA Best Practice to always specify which workbook your VBA code refers. If this specification is omitted, then VBA assumes the code is directed at the currently active workbook (
'--- the currently active workbook (and worksheet) is implied Range("A1").value = 3.1415 Cells(1, 1).value = 3.1415
However, when several workbooks are open at the same time -- particularly and especially when VBA code is running from an Excel Add-In -- references to the
ActiveWorkbook may be confused or misdirected. For example, an add-in with a UDF that checks the time of day and compares it to a value stored on one of the add-in's worksheets (that are typically not readily visible to the user) will have to explicitly identify which workbook is being referenced. In our example, our open (and active) workbook has a formula in cell A1
=EarlyOrLate() and does NOT have any VBA written for that active workbook. In our add-in, we have the following User Defined Function (UDF):
Public Function EarlyOrLate() As String If Hour(Now) > ThisWorkbook.Sheets("WatchTime").Range("A1") Then EarlyOrLate = "It's Late!" Else EarlyOrLate = "It's Early!" End If End Function
The code for the UDF is written and stored in the installed Excel add-in. It uses data stored on a worksheet in the add-in called "WatchTime". If the UDF had used
ActiveWorkbook instead of
ThisWorkbook, then it would never be able to guarantee which workbook was intended.
# Changing The Default Number of Worksheets In A New Workbook
The "factory default" number of worksheets created in a new Excel workbook is generally set to three. Your VBA code can explicitly set the number of worksheets in a new workbook.
'--- save the current Excel global setting With Application Dim oldSheetsCount As Integer oldSheetsCount = .SheetsInNewWorkbook Dim myNewWB As Workbook .SheetsInNewWorkbook = 1 Set myNewWB = .Workbooks.Add '--- restore the previous setting .SheetsInNewWorkbook = oldsheetcount End With
# Application Workbooks
In many Excel applications, the VBA code takes actions directed at the workbook in which it's contained. You save that workbook with a ".xlsm" extension and the VBA macros only focus on the worksheets and data within. However, there are often times when you need to combine or merge data from other workbooks, or write some of your data to a separate workbook. Opening, closing, saving, creating, and deleting other workbooks is a common need for many VBA applications.
At any time in the VBA Editor, you can view and access any and all workbooks currently open by that instance of Excel by using the
Workbooks property of the
Application object. The MSDN Documentation explains it with references.
# Opening A (New) Workbook, Even If It's Already Open
If you want to access a workbook that's already open, then getting the assignment from the
Workbooks collection is straightforward:
dim myWB as Workbook Set myWB = Workbooks("UsuallyFullPathnameOfWorkbook.xlsx")
If you want to create a new workbook, then use the
Workbooks collection object to
Add a new entry.
Dim myNewWB as Workbook Set myNewWB = Workbooks.Add
There are times when you may not or (or care) if the workbook you need is open already or not, or possible does not exist. The example function shows how to always return a valid workbook object.
Option Explicit Function GetWorkbook(ByVal wbFilename As String) As Workbook '--- returns a workbook object for the given filename, including checks ' for when the workbook is already open, exists but not open, or ' does not yet exist (and must be created) ' *** wbFilename must be a fully specified pathname Dim folderFile As String Dim returnedWB As Workbook '--- check if the file exists in the directory location folderFile = File(wbFilename) If folderFile = "" Then '--- the workbook doesn't exist, so create it Dim pos1 As Integer Dim fileExt As String Dim fileFormatNum As Long '--- in order to save the workbook correctly, we need to infer which workbook ' type the user intended from the file extension pos1 = InStrRev(sFullName, ".", , vbTextCompare) fileExt = Right(sFullName, Len(sFullName) - pos1) Select Case fileExt Case "xlsx" fileFormatNum = 51 Case "xlsm" fileFormatNum = 52 Case "xls" fileFormatNum = 56 Case "xlsb" fileFormatNum = 50 Case Else Err.Raise vbObjectError + 1000, "GetWorkbook function", _ "The file type you've requested (file extension) is not recognized. " & _ "Please use a known extension: xlsx, xlsm, xls, or xlsb." End Select Set returnedWB = Workbooks.Add Application.DisplayAlerts = False returnedWB.SaveAs filename:=wbFilename, FileFormat:=fileFormatNum Application.DisplayAlerts = True Set GetWorkbook = returnedWB Else '--- the workbook exists in the directory, so check to see if ' it's already open or not On Error Resume Next Set returnedWB = Workbooks(sFile) If returnedWB Is Nothing Then Set returnedWB = Workbooks.Open(sFullName) End If End If End Function
# Saving A Workbook Without Asking The User
Often saving new data in an existing workbook using VBA will cause a pop-up question noting that the file already exists.
To prevent this pop-up question, you have to suppress these types of alerts.
Application.DisplayAlerts = False 'disable user prompt to overwrite file myWB.SaveAs FileName:="NewOrExistingFilename.xlsx" Application.DisplayAlerts = True 're-enable user prompt to overwrite file