ComboBox Auto-Search With String From ComboBox?

have build some code which goes through the datasource finding records on what a user types, basically if the user types 'P' in the combobox it finds all records from FieldName with 'P' and if you type 'Portugal' it finds all records from the FieldName with 'Portugal, it all narrows down the search list say if there are to entries which match 'Portugal' the combox would only have to items in. The problem i am have is that when i bound the datasource back to the combobox every letter you type stays at Postion 0 of the combobox and doesn't move to the end of the letter as normally the combo works, does any one now how to get arround this problem.

At the moment i call my combobox search code from the keypress event of the combobox.This code works fine with recordsets in msaccess combobox but i cannot get it to work with the datasource of the combobox in vb.net Heres the code from the combobox keypress event:

Private Sub ComboBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles ComboSearch.KeyPress
Dim keyascii As Integer = AscW(e.KeyChar)
PhoneBookComboSearch(keyascii)
End Sub

Below is the code at the end of my keypress event send the datasource back to the combobox.

Dim adapter As New SqlClient.SqlDataAdapter(strSQL, conn)
Dim dt As New DataTable("MyTable")
Dim ds As New DataSet

[code]....