how to get the selectedindexchanged method of combobox is in webusercontrol

hello,
I want to resuse a combobox, so I place combobx into an usercontrol, but how to get the selectedindexchanged method and selected value where the page uses the usercontrol?

WEBUSERCONTROL

Code:

---

<ext:ComboBox ID="cb1" runat="server" StoreID="strEstabl" Editable="false"
            TypeAhead="true" Mode="Local" TriggerAction="All" DisplayField="Descripcion" ValueField="co_esta"
            Width="470px" SelectOnFocus="true" ForceSelection="true">
            <SelectedItem Value="0" />
<DirectEvents>
                <Change OnEvent="GetTempo"></Change>
            </DirectEvents>
            </ext:ComboBox>

---

ASP.NET PAGE

Code:

---

<wuc1:wucTest ID="wucTest " runat="server"  />

---

the gettempo method should be in the aspx page and not in the usercontrol, but I do not know how to do that.

Thanks for you help.