Use the same workbook in multiple modules - excel

Question

I have a workbook with two buttons. So an user can press them to open two workbooks (Input and Output). Then he will copy data from Input to Output. My problem here is that I don't know how to define the same workbook for my subs.
This is the code for opening the files:
Public wb1 As Workbook
Public wb2 As Workbook
Public result As Integer
Public fDialog As FileDialog
Public Sub inputs()
Set fDialog = Application.FileDialog(msoFileDialogOpen)
Set control = Workbooks("Control.xlsm").Worksheets("Control")
fDialog.Title = "Select a file"
fDialog.Title = "Select a file"
If fDialog.Show = -1 Then
If Right(fDialog.SelectedItems(1), 5) = ".xlsx" Or Right(fDialog.SelectedItems(1), 4) = ".xls" Then
Set wb1 = Workbooks.Open(fDialog.SelectedItems(1))
control.Cells(6, 2) = fDialog.SelectedItems(1)
Else
MsgBox ("Please select an excel file")
Exit Sub
End If
End If
End Sub
This is the other sub for copying data:
Public Sub stack()
For Each ws In wb1.Worksheets
'---here is the code for copying data---
Exit For
Exit Sub
When I run this code, of course it gives me this error "object variable or With block not set".
Do you know how can I resolve this? How can I use the same wb1 for both subs?

Answer 1

It's better to limit the scope of your variable whenever possible so what you can do is this:
Public Sub stack()
Dim wbControl As Worksheet
Set wbControl = Workbooks("Control.xlsm").Worksheets("Control")
'Check if there is possible input path in cell B6
If wbControl.Cells(6, 2).Value2 = vbNullString Then
MsgBox "Provide the Input workbook path first!"
Exit Sub
End If
'Check if there is possible output path in cell B6
If wbControl.Cells(6, 2).Value2 = vbNullString Then
MsgBox "Provide the Output workbook path first!"
Exit Sub
End If
'More error checking - e.g. check if both path are valid (file exist?)
Dim wbInput As Workbook
Set wbInput = Workbooks.Open(wbControl.Cells(6, 2).Value2) 'Input path in cell B6
Dim wbOutput As Workbook
Set wbOutput = Workbooks.Open(wbControl.Cells(6, 5).Value2) 'Output path in cell E6
Dim ws As Worksheet
For Each ws In wbInput.Worksheets
'Do whatever you want in here
Next ws
'Remember to close the workbook if not needed later
End Sub
Remove this line from your inputs sub (and also similar one for selecting the output file)
Set wb1 = Workbooks.Open(fDialog.SelectedItems(1))

Answer 2

Please, use the next way:
Declare public variables for both necessary workbooks, on top of the standard module:
Public wb1 As Workbook, wb2 As Workbook
Copy the next sub in a standard module, to open and Set the necessary workbooks:
Sub SetWorbooks()
Dim fdialog As FileDialog, i As Long
Set fdialog = Application.FileDialog(msoFileDialogFilePicker)
For i = 1 To 2
fdialog.Title = "Please, select """ & IIf(i = 1, "Input", "Output") & """ file"
If fdialog.Show = -1 Then
If Right(fdialog.SelectedItems(1), 5) = ".xlsx" Or Right(fdialog.SelectedItems(1), 4) = ".xls" Then
If i = 1 Then
Set wb1 = Workbooks.Open(fdialog.SelectedItems(1))
Else
Set wb2 = Workbooks.Open(fdialog.SelectedItems(1))
End If
Else
MsgBox "Please select an excel file (xls, xlsx)!"
Exit Sub
End If
Else
MsgBox "You should select an Excel file...": Exit Sub
End If
Next i
End Sub
Then use them in this way:
Sub Mystack()
Dim ws As Worksheet
If wb1 Is Nothing Then SetWorbooks 'for cases when having an error and the wb(s) reference have been lost.
For Each ws In wb1.Worksheets
'---here is the code for copying data---
Next
End Sub