<asp:SqlDataSource ID="SqlDataSource" runat="server" ConnectionString="<%$ ConnectionStrings:ConnectionString %>" 
SelectCommand="SELECT [IDP], [NOMP] FROM [Pd] WHERE ([IDF]=@IDF) Order By IDPDL">
<SelectParameters>
              <asp:SessionParameter SessionField="id" Type="Int32" Name="IDF" />
</SelectParameters>
</asp:SqlDataSource>                                                                      
<asp:DropDownList ID="Drop_Pd" Runat="server" DataSourceID="SqlDataSource" DataTextField="NOMPD" DataValueField="IDPD" Width="100" AutoPostBack="True" />