An XL file IS a workbook.
For me, outside of XL (in the OS/File System etc) it is a file, whilst when
opened in XL it is a workbook.
There can only be 1 workbook in a file. It can however have multiple
Worksheets.
Assuming you are referring to whether the WB is hidden when opened (the
default for Personal.xls), try this VBA.

Private Sub CommandButton1_Click()
Dim FileNames() As String
Dim i As Long
Dim WB As Workbook
Dim RetVal As Boolean

'Fill the values from list
'FileNames() = ???

For i = LBound(FileNames) To UBound(FileNames)
Set WB = Workbooks.Open(FileNames(i))
RetVal = IsWBHidden(WB)
'Save the result somewhere
WB.Close False
Next

End Sub

Private Function IsWBHidden(WB As Workbook) As Boolean
Dim i As Long
IsWBHidden = True
With WB.Windows
For i = 1 To .Count
If .Item(i).Visible = True Then
IsWBHidden = False
Exit Function
End If
Next
End With
End Function

NickHK

"sparrow" wrote in message
oups.com...
I am pretty new to coding in VB.NET. I wanted to write a code to search
through a list of Excel files and find those files that have a hidden
workbook. I tried to capture the value of
mExcelObj.ActiveWindow.Visible into a string and check if it is true or
false, based on which I could identify whether the Excel file has a
hidden workbook or not. Any guidance would be appreciated.

Thanks