VB.NET delete duplicates in a paritcular range - vb.net

Question

My app below checks a workbook which has a list of items sold for a particular month identified with a serial number. There is also a comment column next to the item.
Each month when I run the app it tells me if the same item was sold and the comments next to the item.
"Item found in sheet labeled august 2014"
"Comments for that item"
if I run the app again on the workbook when it gets an additional sheet added, it's going to add the "items found..." Again.
I have the results starting from column 20 and beyond, I only need to delete the duplicates in those columns.
Option Explicit On
Option Infer Off
Imports System.Net.Mail
Imports System.IO
Imports Microsoft.Office.Interop
Imports Microsoft.Office.Interop.Excel
Imports System.Runtime.InteropServices
Imports Excel = Microsoft.Office.Interop.Excel
Imports System.Text.RegularExpressions
Public Class Form1
Dim fileName As String = ""
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
End Sub
Private Function ColumnIndexToColumnLetter(colIndex As Integer) As String
Dim div As Integer = colIndex
Dim colLetter As String = String.Empty
Dim modnum As Integer = 0
While div > 0
modnum = (div - 1) Mod 26
colLetter = Chr(65 + modnum) & colLetter
div = CInt((div - modnum) \ 26)
End While
Return colLetter
End Function
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Button1.Enabled = False
Button1.Text = "Patience"
Button1.Refresh()
System.Windows.Forms.Application.DoEvents()
Dim app As New Excel.Application
app.Visible = False
Dim wbBase As Excel.Workbook = app.Workbooks.Open(TextBox1.Text)
' * create style *
'
Dim xlStyles As Excel.Styles = wbBase.Styles
Dim xlStyle As Excel.Style = Nothing
Dim isstyleexists As Boolean = False
'
' * check if this style exist *
'
For Each xlStyle In xlStyles
If xlStyle.Name = "NewStyle" Then
isstyleexists = True
Exit For
End If
Next
'
' * if this does not exist so add new one *
' ' get Range "A1"
If (Not isstyleexists) Then
xlStyles.Add("NewStyle")
xlStyle = xlStyles.Item("NewStyle")
End If
Dim snName As String
Dim snName2 As String
Dim cmt2 As String
For Each basesheet As Excel.Worksheet In wbBase.Sheets
Dim iiii As Integer = basesheet.Cells(1, basesheet.Columns.Count).End(Excel.XlDirection.xlToLeft).Column + 1
Dim iii As Integer = basesheet.Cells(1, basesheet.Columns.Count).End(Excel.XlDirection.xlToLeft).Column + 1
Dim iv As Integer = iii + 1
For i As Integer = 1 To 20
If Not basesheet.Cells(1, i).Value Is Nothing AndAlso basesheet.Cells(1, i).Value.Contains("Serial Number") Then
snName = ColumnIndexToColumnLetter(i)
Exit For
End If
Next
If Not snName Is Nothing Then
For Each checksheet As Excel.Worksheet In wbBase.Sheets
If basesheet.Name <> checksheet.Name Then
For i As Integer = 1 To 20
If Not checksheet.Cells(1, i).Value Is Nothing AndAlso checksheet.Cells(1, i).Value.Contains("Serial Number") Then
snName2 = ColumnIndexToColumnLetter(i)
Exit For
End If
Next
For i As Integer = 1 To 20
If Not checksheet.Cells(1, i).Value Is Nothing AndAlso checksheet.Cells(1, i).Value.Contains("Comments") Then
cmt2 = ColumnIndexToColumnLetter(i)
Exit For
End If
Next
If Not snName2 Is Nothing Then
Dim baseobj As Object = basesheet.Range(snName & "2:" & snName & basesheet.Range(snName & basesheet.Rows.Count).End(Excel.XlDirection.xlUp).Row).Value
Dim checkobj As Object = checksheet.Range(snName2 & "2:" & snName2 & checksheet.Range(snName2 & checksheet.Rows.Count).End(Excel.XlDirection.xlUp).Row).Value
Dim cmtobj As Object = checksheet.Range(cmt2 & "2:" & cmt2 & checksheet.Range(snName2 & checksheet.Rows.Count).End(Excel.XlDirection.xlUp).Row).Value
Dim basetmp(DirectCast(baseobj, Object(,)).Length, 1) As Object
Dim v As Integer = 0
Dim bool As Boolean = False
For i As Integer = 1 To DirectCast(baseobj, Object(,)).Length
For ii As Integer = 1 To DirectCast(checkobj, Object(,)).Length
If Not baseobj(i, 1) Is Nothing AndAlso Not checkobj(ii, 1) Is Nothing AndAlso Trim(baseobj(i, 1).ToString) = Trim(checkobj(ii, 1).ToString) Then
bool = True
basetmp(i, 0) = "Serial # Exists in " & checksheet.Name
basetmp(i, 1) = cmtobj(ii, 1)
End If
Next
v += 1
Next
If bool Then
basesheet.Range(basesheet.Cells(1, iii), basesheet.Cells(v, iv)).Style = "NewStyle"
basesheet.Range(basesheet.Cells(1, iii), basesheet.Cells(v, iv)).Borders.Weight = Excel.XlBorderWeight.xlThin
basesheet.Range(basesheet.Cells(1, iii), basesheet.Cells(v, iv)).Borders.LineStyle = Excel.XlLineStyle.xlContinuous
basesheet.Range(basesheet.Cells(1, iii), basesheet.Cells(v, iv)).Value = basetmp
basesheet.Cells(1, iii).value = "Results Found"
basesheet.Cells(1, iii).Font.Color = System.Drawing.ColorTranslator.ToOle(System.Drawing.Color.Red)
basesheet.Cells(1, iii).HorizontalAlignment = Excel.Constants.xlCenter
basesheet.Cells(1, iii).Font.Bold = True
basesheet.Columns.AutoFit()
iii += 2
iv += 2
End If
End If
End If
Next
End If
Next
wbBase.Save()
wbBase.Close()
app.Quit()
MessageBox.Show("Done", "Three in Thirty", MessageBoxButtons.OK)
Button1.Text = "Start"
Button1.Enabled = True
End Sub

Answer 1

It looks like you are reprocessing the previously processed sheets each month.
It might be easier to avoid reprocessing old sheets, than to avoid duplicating entries from reprocessing old sheets.
Instead of using nested loops of worksheets, I would probably try a pattern like:
* find basesheet
* find latest checksheet
* process the checksheet for items sold
If users might accidentally add things to old sheets, then I would consider locking old sheets when you do the processing to help ensure data integrity.