Programming Excel with VBA and .NET

Sequential Access

Sequential access reads and writes files one line at a time. In the past, sequential access was often used to write reports or other data to human-readable files. For example, the following WriteArray function writes a two-dimensional array to disk as a comma-delimited file using sequential access:

    ' Writes a two-dimensional array to a comma-delimited file.
    ' (Use to create CSV file out of a selected range.)
    Function WriteArray(arr As Variant, fname As String, _
      Optional overwrite As Boolean = False) As Boolean
        Dim lb1 As Long, lb2 As Long, ub1 As Long, ub2 As Long
        Dim i As Integer, rows As Long, cols As Long, rec As String
        ' If arr isn't an array, return False and exit.
        If Not IsArray(arr) Then WriteArray = False: Exit Function
        ' Get bounds for For loops.
        lb1 = LBound(arr, 1)
        lb2 = LBound(arr, 2)
        ub1 = UBound(arr, 1)
        ub2 = UBound(arr, 2)
        ' If file exists and overwrite is True, then
        If Dir(fname) <> "" Then
            If overwrite Then
                ' delete the file.
                Kill fname
            Else
                ' else, return False and exit.
                WriteArray = False
                Exit Function
            End If
        End If
        ' Get a free file handle.
        i = FreeFile
        ' Open the file.
        Open fname For Append As #i
        ' For each row in the array.
        For rows = lb1 To ub1
            ' For each column in the array.
            For cols = lb2 To ub2
                rec = rec & arr(rows, cols) & ", "
            Next
            ' Remove the last ", " from rec.
            rec = Left(rec, Len(rec) - 2)
            ' Write rec to the file.
            Print #i, rec
            ' Clear rec
            rec = ""
        Next
        ' Close the file
        Close i
        ' Return True.
        WriteArray = True
    End Function

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