Dim stringa As String = "server=(local);database=TUODATABASE;trusted_conne ction=true"
Dim connessione As New SqlConnection(stringa)

Sub Page_Load(Sender As Object, E As EventArgs)
If Not Page.IsPostBack Then
Dim comando1 As String = "select marca from marche"
Dim connessione As New SqlConnection(stringa)
Dim myCommand As New SqlCommand(comando1, connessione)
connessione.Open()
lsmarche.DataSource = myCommand.ExecuteReader(CommandBehavior.CloseConne ction)
lsmarche.DataBind()
lsmarche.Items.Insert(0, "-- Seleziona una marca --")
End If
End Sub

Sub DropDownList1_SelectedIndexChanged(sender As Object, e As EventArgs)
Dim id As String = "select modello from modelli where marcaid = (select marcaid from Marche where marca=" & "'" &(lsmarche.Items(lsmarche.SelectedIndex).text) & "')"
Dim comando2 As New SqlCommand(id, connessione)
connessione.Open()
lsmodelli.DataSource = comando2.ExecuteReader(CommandBehavior.CloseConnec tion)
lsmodelli.DataBind()
End Sub

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