Coolite ComboBox中显示树

<ext:ComboBox ID="ComboBox1" runat="server" Width="250" Editable="false" Mode="Local"
ForceSelection="false" MaxHeight="200" AllowBlank="true">
<Items>
<ext:ListItem />
</Items>
<Template ID="Template1" runat="server">

<div id="myTree" style="height:200px"></div>
</Template>
<Listeners>
<Expand Handler="#{TreePanel1}.render('myTree');" />
</Listeners>
</ext:ComboBox>

<ext:TreePanel ID="TreePanel1" AutoRender="false" runat="server" Border="false" Icon="BookOpen"
AutoScroll="false">
<Root>
<ext:TreeNode Text="Composers" Expanded="true">
<Nodes>
<ext:TreeNode Text="Beethoven" Icon="UserGray">
<Nodes>
<ext:TreeNode Text="Concertos">
<Nodes>
<ext:TreeNode Text="No. 1 - C" NodeID="1" Icon="Music" />
<ext:TreeNode Text="No. 2 - B-Flat Major" NodeID="2" Icon="Music" />
<ext:TreeNode Text="No. 3 - C Minor" NodeID="3" Icon="Music" />
<ext:TreeNode Text="No. 4 - G Major" NodeID="4" Icon="Music" />
<ext:TreeNode Text="No. 5 - E-Flat Major" NodeID="5" Icon="Music" />
</Nodes>
</ext:TreeNode>
<ext:TreeNode Text="Quartets">
<Nodes>
<ext:TreeNode Text="Six String Quartets" Icon="Music" />
<ext:TreeNode Text="Three String Quartets" Icon="Music" />
<ext:TreeNode Text="Grosse Fugue for String Quartets" Icon="Music" />
</Nodes>
</ext:TreeNode>
<ext:TreeNode Text="Sonatas">
<Nodes>
<ext:TreeNode Text="Sonata in A Minor" Icon="Music" />
<ext:TreeNode Text="sonata in F Major" Icon="Music" />
</Nodes>
</ext:TreeNode>
<ext:TreeNode Text="Symphonies">
<Nodes>
<ext:TreeNode Text="No. 1 - C Major" Icon="Music" />
<ext:TreeNode Text="No. 2 - D Major" Icon="Music" />
<ext:TreeNode Text="No. 3 - E-Flat Major" Icon="Music" />
<ext:TreeNode Text="No. 4 - B-Flat Major" Icon="Music" />
<ext:TreeNode Text="No. 5 - C Minor" Icon="Music" />
<ext:TreeNode Text="No. 6 - F Major" Icon="Music" />
<ext:TreeNode Text="No. 7 - A Major" Icon="Music" />
<ext:TreeNode Text="No. 8 - F Major" Icon="Music" />
<ext:TreeNode Text="No. 9 - D Minor" Icon="Music" />
</Nodes>
</ext:TreeNode>
</Nodes>
</ext:TreeNode>
</Nodes>
</ext:TreeNode>
</Root>
<Listeners>
<Click Handler="#{ComboBox1}.setValue(node.text);#{ComboBox1}.collapse();" />
<%--<Click Handler="if(!node.hasChildNodes()){#{ComboBox1}.setValue(node.text);#{ComboBox1}.collapse();}" />--%>
</Listeners>
</ext:TreePanel>