Dim adptr As New OleDbDataAdapter("Select * from[u]" And _
  Wagentyp.SelectedItem, con)
 
adptr.Fill(ds, [u]Wagentyp.SelectedItem)
 
Dim cmd As New OleDbCommand("Select * from[u]" And Wagentyp.SelectedItem And _
  "WHERE Auswahl ='" & ComboBox2.SelectedItem & "'", con)

Dim adptr As New OleDbDataAdapter("Select * from Auto1" , con)
 
adptr.Fill(ds, "Auto1")
 
Dim cmd As New OleDbCommand("Select * from Auto1 WHERE Auswahl = '" & _
  ComboBox2.SelectedItem & "'",con)

    Public Sub loadData()
        Dim ds As New DataSet
        Dim dr As DataRow
        Dim dt As New DataTable
        Dim adptr As New OleDbDataAdapter("select * from Auto1", con)
        adptr.Fill(ds, "Auto1")
        dt = ds.Tables(0)
        For Each dr In dt.Rows
            ComboBox2.Items.Add(dr.Item("Auswahl"))
        Next
        Call clearMitteilung()
    End Sub
 
    Private Sub ComboBox2_SelectedIndexChanged(ByVal sender As System.Object, _
      ByVal e As System.EventArgs) Handles ComboBox2.SelectedIndexChanged
 
        Try
            Call clearMitteilung()
            If con.State = ConnectionState.Closed Then con.Close()
            con.Open()
            Dim cmd As New OleDbCommand("select * from Auto1 WHERE Auswahl = '" _
              & ComboBox2.SelectedItem & "'", con)
            Dim drdr As OleDbDataReader
            drdr = cmd.ExecuteReader
            drdr.Read()
            EB.Text = drdr.Item("BMW")
            EBTxT.Text = drdr.Item("Audi")
            NF.Text = drdr.Item("VW")
            cmd.Cancel()
            con.Close()
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
    End Sub