Ext Combobox+tree的扩张方法

Code
  var comboxWithTree = new Ext.form.ComboBox({
            store: new Ext.data.SimpleStore({ fields: [], data: [[]] }),
            editable: false,
            shadow: false,
            mode: 'local',
            triggerAction: 'all',
            maxHeight: 200,
            tpl: '<tpl for="."><div style="height:200px"><div id="tree1"></div></div></tpl>',
            selectedClass: '',
            onSelect: Ext.emptyFn
        });
        var tree1 = new Ext.tree.TreePanel({
            loader: new Ext.tree.TreeLoader({ dataUrl: 'JsonTest.aspx' }),
            border: false,
            root: new Ext.tree.AsyncTreeNode({ text: 'treeRoot', id: '0' })
        });
        tree1.on('click', function(node) {
            comboxWithTree.setValue(node.text);
            comboxWithTree.collapse();
        });
        comboxWithTree.on('expand', function() {
            tree1.render('tree1');
        });
       comboxWithTree.render('cCord');//要显示得容器