title: AJAX ModalPopup update panel contents based on change in panel controls
body: <p>I have an AJAX Modal Popup panel that contains a RadioButtonList, 2 labels and 2 DropDowns.  I want to update the Labels and DropDowns when a radio button is selected.  My attempt at this posts back which causes the ajax popup to disappear.</p>
  
  <p>aspx called on image click:</p>
  
  <pre><code>&lt;asp:Panel ID="pnlModalContainer" runat="server"&gt;
      &lt;asp:RadioButtonList ID="rblTest" runat="server" RepeatDirection="Horizontal" OnSelectedIndexChanged="rblTest_SelectedIndexChanged"&gt;
        &lt;asp:ListItem Text="Test 1" Value="1" Selected="True" /&gt;
        &lt;asp:ListItem Text="Test 2" Value="2" /&gt;
      &lt;/asp:RadioButtonList&gt;
      &lt;br /&gt;
      &lt;asp:Label ID="lblFoo" Text="Foo" /&gt;
      &lt;asp:Label ID="lblBar" Text="Bar" /&gt;
      &lt;asp:DropDownList ID="ddlDogs" runat="server" DataSourceID="odsDogs" DataTextField="Dog" DataValueField="DogID" /&gt;
      &lt;asp:DropDownList ID="ddlCats" runat="server" DataSourceID="odsCats" DataTextField="Cat" DataValueField="CatID" /&gt;
  &lt;/asp:Panel&gt;
  </code></pre>
  
  <p>Code Behind (vb.net):</p>
  
  <pre><code>Protected Sub rblTest_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs) Handles rblTest.SelectedIndexChanged
     ' ???
     ' Make it change lblFoo.Text and lblBar.Text as well as the DataSource for the DDLs
  End Sub
  </code></pre>