dropdownbox Selecteditem

[cartman83]

I've got a dropdownbox with a few values in it. There is one value that is selected in advance. But when I change the value in the dropdownbox to a larger amount and press "Search" the value that continues is the standard value.
Here is my code:

Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    FillList()
    End Sub
 
    Private Sub FillList()
        Dim oNewTable As HtmlTable
        Dim oNewRow As HtmlTableRow
        Dim oNewCell As HtmlTableCell
    Dim oNewListItem As ListItem
    Dim oNewImageButton As ImageButton
    oNewRow = New HtmlTableRow
    oNewCell = New HtmlTableCell
    Dim i As Integer = 0
    Dim iMonth(5) As Integer
    iMonth(0) = 1
    iMonth(1) = 3
    iMonth(2) = 6
    iMonth(3) = 12
    iMonth(4) = 20
 
    While i < 5
        If i=0 Then
                oNewListItem = New ListItem
                With oNewListItem
                          .Value = iMonth(i)
                           .Text = iMonth(i) &" month"
                End With
            lstSales.Items.Add(oNewListItem)
        Elseif i=4 Then
                oNewListItem = New ListItem
                With oNewListItem
                           .Value = iMonth(i)
                           .Text = "All"
                End With
            lstSales.Items.Add(oNewListItem)
        Else
                oNewListItem = New ListItem
                With oNewListItem
                           .Value = iMonth(i)
                           .Text = iMonth(i) &" months"
                End With
            lstSales.Items.Add(oNewListItem)
        End If
        i+=1
    End While
    lstSales.Items(1).Selected = True
 
    End Sub
 
    Private Sub btnSearch_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnSearch.Click
     Response.Redirect("rptSalesProjectsGraph.aspx?ID=" & lstSales.SelectedItem.Value)
    End Sub
 

So 3 months is standard, but when I want to change is to, for example, 6 months it stays 3 months. But when I change it to 1 month it works perfectly.