Checking if a Workbook is Already Open

Macros are often used to slice, dice, and otherwise process information contained in workbooks. This presumes, of course, that the workbook that contains the information is actually open. If it is not, then your macro will obviously need to include code to actually open the needed workbook.

Opening a workbook can really slow down a macro; it takes time to access the disk and load the file. Thus, if your macro can check to see if a workbook is open before going through the hassle of actually trying to open it, you could speed up your macros greatly if the workbook is found to already be open.

One very flexible way to approach the task of checking whether a workbook is open is to use a function that does the checking, and then simply returns a TRUE or FALSE value based on whether the workbook is open. The following short macro performs this succinct task:

Function AlreadyOpen(sFname As String) As Boolean
    Dim wkb As Workbook
    On Error Resume Next
    Set wkb = Workbooks(sFname)
    AlreadyOpen = Not wkb Is Nothing
    Set wkb = Nothing
End Function

To use the function, just pass it the name of the workbook you want to check, in the following manner:

    sFilename = "MyFileName.xls"
    sPath = "C:\MyFolder\MySubFolder\"
    If AlreadyOpen(sFilename) Then
        'Do not have to open
    Else
        Workbooks.Open sPath & sFilename
    End If