Visual Studio macro: Get path of previous/next document

How to get the path of previous active document & previous/next document on tab bar?

'Get current 开发者_如何学Pythonactive document
Dim file1 As String = DTE.ActiveDocument.FullName

'Get previous active document
Dim file2 As String = 

'Get previous/next document (position on tab bar)
Dim file3 As String = 

Thanks.

Not sure if this is the best way to do it, but I figured out to get the previous/next document on tab bar using the following code:

    Dim activeDocument As String = DTE.ActiveDocument.FullName
    Dim nextDocument As String

    'Get next document
    Dim found As Boolean = False
    Dim i As Integer
    For i = 1 To DTE.Windows.Count Step 1
        If DTE.Windows().Item(i).Kind = "Document" Then
            If DTE.Windows().Item(i) Is DTE.ActiveWindow Then
                found = True
            ElseIf found Then
                nextDocument = DTE.Windows().Item(i).Document.FullName
                Exit For
            End If
        End If
    Next

But not sure how to get the previous active document.