how can I use updatepanel for more than 1 control - asp.net

Question

<div class="step-content">
<div class="step-pane active" id="step1">
<div class="control-group ">
<label class="control-label" for="inputWarning">Please select the Event Name</label>
<div class="controls">
<asp:DropDownList ID="DropDownList1" runat="server" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged" AutoPostBack="True" DataSourceID="SqlDataSource1" DataTextField="EventName" DataValueField="EventId"></asp:DropDownList>
<asp:SqlDataSource runat="server" ID="SqlDataSource1" ConnectionString='<%$ ConnectionStrings:WBENCConnectionString %>' SelectCommand="SELECT [EventId], [EventName] FROM [Event]"></asp:SqlDataSource>
</div>
</div>
</div>
<div class="step-pane" id="step2">
<div class="control-group " >
<asp:Label ID="DateLabel" runat="server"></asp:Label>
<div class="controls">
<asp:UpdatePanel ID="UpdatePanel2" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<asp:RadioButtonList ID="RadioButtonList1" runat="server" OnSelectedIndexChanged="RadioButtonList1_SelectedIndexChanged" AutoPostBack="true">
<asp:ListItem Text="Yes" Value="Yes"></asp:ListItem>
<asp:ListItem Text="No" Value="No"></asp:ListItem>
</asp:RadioButtonList>
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="RadioButtonList1" EventName="SelectedIndexChanged"/>
</Triggers>
</asp:UpdatePanel>
</div>
</div>
</div>
<div class="step-pane" id="step3">
<div class="control-group ">
<label class="control-label" for="inputWarning">
<span class="muted">You can learn more about the program here</span></label>
<div class="controls">
<label class="radio">
<asp:RadioButton ID="Radio1" runat="server" Text="Yes" value="option1" /></label>
<label class="radio">
<asp:RadioButton ID="Radio2" runat="server" Text="No" value="option2" /></label>
<label class="radio">
<asp:RadioButton ID="Radio3" runat="server" Text="Uncertain" value="option2" /></label>
</div>
</div>
</div>
<div class="step-pane" id="step4">
<div class="control-group">
<label class="control-label" for="selectError30">Which days will you be available to participate in the Matchmaker Sessions?</label>
<div class="controls">
<asp:DropDownList ID="selectError30" runat="server" OnDataBound="selectError30_DataBound">
</asp:DropDownList>
</div>
</div>
<div class="control-group">
<label class="control-label">Upload your capability statement. <a style="color: #67c2ef;" href="#">What's this?</a></label>
<div class="controls">
<asp:FileUpload ID="FileUpload1" runat="server" />
</div>
</div>
</div>
here the DropDownlist1_onselectedIndexChanged event got full page load..
and RadioButtonList1 event also get page load...
here how can I use the Update Panel to overcome the full page load....
In my code all events perform Page_Load....
I want to prevent that loading....

Answer 1

If there is a full page load then since panel is inside the page, it will also get refreshed. You can put the drop down inside another update panel. This will prevent the refreshing of radio button update panel.