try this...
Public Sub FillCombo(ByVal combo As ComboBox, ByVal sSQL As String, ByVal sTable As String, ByVal sNum As Integer)
Dim totalRow As Long = 0
Dim da As New OleDb.OleDbDataAdapter(sSQL, con)
Dim ds As New DataSet
Dim i As Integer
dim totalRow as integer
ds = New DataSet()
da.Fill(ds, sTable)
totalRow = ds.Tables(sTable).Rows.Count - 1
combo.Items.Clear()
For i = 0 To totalRow
combo.Items.Add("" & ds.Tables(sTable).Rows(i).ItemArray.GetValue(0).ToString())
Next
If (combo.Items.Count > 0) Then combo.SelectedIndex = 0
If sNum = 1 Then combo.Items.Add("ALL")
End Sub