Ciao a tutti,
vorrei sfruttare gli update panel per delle select in sequenza, tutto questo in un file .ascx.
Ecco il codice che ho:
codice:
<div class="box180 floatL h26 marginT80">
                <asp:DropDownList ID="ddlContinents1" runat="server" CssClass="select" ValidationGroup="richiesta" OnSelectedIndexChanged="ddlContinents1_SelectedIndexChanged" >
                        <asp:ListItem Text="Seleziona" Value = "0"></asp:ListItem>                 
                </asp:DropDownList>
            </div>
            <div class="box100 floatL txtWhite11 h26">Provincia</div>
            <div class="box180 floatL h26">
                <asp:UpdatePanel ID="UpdatePanel1" runat="server">
                <ContentTemplate>
                 <asp:DropDownList ID="ddlCountries1" runat="server" CssClass="input" ValidationGroup="richiesta">
                        <asp:ListItem Text = "Seleziona" Value = "0"></asp:ListItem>                 
                 </asp:DropDownList>                 
                 </ContentTemplate>
                 <Triggers>
                    <asp:AsyncPostBackTrigger ControlID="ddlContinents1" EventName="SelectedIndexChanged" />
                 </Triggers>
                 </asp:UpdatePanel>
            </div>
            <div class="box100 floatL txtWhite11 h26">Comune</div>
            <div class="box180 floatL h26">
                 <asp:DropDownList ID="ddlCities1" runat="server" CssClass="input"  Width="190px" ValidationGroup="richiesta">
                        <asp:ListItem Text = "Seleziona" Value = "0"></asp:ListItem>                 
                 </asp:DropDownList>
            </div>
.VB:
codice:
Public Sub PopulateContinents1(ByVal ddlContinents As DropDownList)
        Try
            connetti()

            Dim strConnString As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
            Dim strQuery As String = "select idregione, regione from Regioni"
            Dim con As MySqlConnection = New MySqlConnection(strConnString)
            Dim cmd As MySqlCommand = New MySqlCommand
            cmd.CommandType = CommandType.Text
            cmd.CommandText = strQuery
            cmd.Connection = con
            con.Open()
            ddlContinents1.DataSource = cmd.ExecuteReader
            ddlContinents1.DataTextField = "regione"
            ddlContinents1.DataValueField = "idregione"
            ddlContinents1.DataBind()
            con.Close()

        Catch errore As Exception
            messaggio.Text = "Si è verificato il seguente errore: " & errore.Message
        Finally
            conn.Close()
        End Try
    End Sub

    
    Protected Sub ddlContinents1_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ddlContinents1.SelectedIndexChanged
        Try
            connetti()
            Dim strConnString As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
            Dim strQuery As String = "select idprovincia, provincia from Province where idregione=" & ddlContinents1.SelectedItem.Value
            Dim con As MySqlConnection = New MySqlConnection(strConnString)
            Dim cmd As MySqlCommand = New MySqlCommand
            cmd.CommandType = CommandType.Text
            cmd.CommandText = strQuery
            cmd.Connection = con
            con.Open()
            ddlCountries1.DataSource = cmd.ExecuteReader
            ddlCountries1.DataTextField = "provincia"
            ddlCountries1.DataValueField = "idprovincia"
            ddlCountries1.DataBind()
            con.Close()

            UpdatePanel1.Visible = True

        Catch errore As Exception
            messaggio.Text = "Si è verificato il seguente errore: " & errore.Message
        Finally
            conn.Close()
        End Try
    End Sub
Mi carica la prima select ma poi al selectchange non fa nulla.
Cosa sbaglio?

Grazie a tutti.