Anasayfa.aspx

 Divlerin gösterilmesini sağlayan JavaScript kodu:

function Blok_Goster(kontrol) {
            $("#sagblok > div").css("display", "none");
            $("#" + kontrol).css("display", "block");
}

"sagblok" adlı bir div var bunun içinde bir adet UpdatePanel mevcut ve bunun için 3 tane div mevcut.

<asp:UpdatePanel ID="pnl_jx" runat="server">
                <ContentTemplate>
                    <div id="sagblok" class="sagblok">

                                    <div id="div1">

                                             <asp:DropDownList ID="ddl1"></asp:DropDownList>

                                     </div>

                                    <div id="div2">

                                              <asp:DropDownList ID="ddl2"></asp:DropDownList>

                                    </div>

                                    <div id="div3">

                                              <asp:DropDownList ID="ddl1"></asp:DropDownList>

                                     </div>

                   </div>

                   </ContentTemplate>

                   <Triggers>

                         <asp:AsyncPostBackTrigger ControlID="ddl_1" EventName="SelectedIndexChanged" />

                         <asp:AsyncPostBackTrigger ControlID="ddl_2" EventName="SelectedIndexChanged" />

                         <asp:AsyncPostBackTrigger ControlID="ddl_3" EventName="SelectedIndexChanged" />

                   </Trigger>

 </UpdatePanel>

Kodlar bu şekilde. Yardımınızı bekliyorum :)

Ayrı ayrı UpdatePanel kullandım problemi hallettim...