ASP.NET MVC 異步獲取和刷新ExtJS6 TreeStore

var mTreeStore = null;
Ext.Ajax.request({
    async: false,
    url: '/api/BasicData_API/GetBasicTablesTreeSource',
    method: 'get',
    success: function (response, options)
    {
      var TreeRoot = Ext.decode(response.responseText);
      mTreeStore = Ext.create('Ext.data.TreeStore',
      {
        root: TreeRoot
      });
    },
    failure: function (response, options)
    {
      //var responseArray = Ext.decode(response.responseText);
      Ext.Msg.alert('服務器錯誤', '數據處理錯誤原因:\n\r' + response.responseText);
    }
});

function TreeStoreRefresh()
{
  Ext.Ajax.request({
    async: false,
    url: '/api/BasicData_API/GetBasicTablesTreeSource',
    method: 'get',
    success: function (response, options)
    {
      var TreeRoot = Ext.decode(response.responseText);
      if (mTreeStore != null)
      {
        mTreeStore.setRoot(TreeRoot);
      }
    },
    failure: function (response, options)
    {
      //var responseArray = Ext.decode(response.responseText);
      Ext.Msg.alert('服務器錯誤', '數據處理錯誤原因:\n\r' + response.responseText);
    }
  });
}

Ext.define('TreeToolbarCls', {
  extend: 'Ext.toolbar.Toolbar',
  padding:'0 0 0 0',
  items: [{
    text: '刷新',
    iconCls: 'refresh',
    handler: TreeStoreRefresh,
    height: 30,
    width: 65
  }]
});

Ext.define('U1TreeCls',
{
  extend: 'Ext.tree.Panel',
  xtype: 'U1Tree_xtype',
  //title: '基礎數據字典',
  rootVisible: true,
  width: 300,
  store: mTreeStore,
  scrollable: true,
  tbar:Ext.create('TreeToolbarCls'),
  listeners:
  {
    itemclick: NodeClick
  }
});

function NodeClick(node, record, item, index, e, eOpts)
{

  if (typeof (record.data) == "undefined")
  {
    return;
  }
  var message = Ext.String.format('Level={0}<br/>state={1}', record.data.Level, record.data.state);
  Ext.Msg.alert("節點信息", message);
}

  [Authorize]
  [RoutePrefix("api/BasicData_API")]
  public class BasicData_APIController : ApiController
  {
    [Route("GetBasicTablesTreeSource")]
    public HttpResponseMessage GetBasicTablesTreeSource(string condition = null)
    {
      List<TreeNode> lstF = new List<TreeNode>();
      ZydAdonet z = ZydAdonet.Instance();
      string s1 = "select TableName,title from BaseDataTables order by TableName";
      string sqltext = s1;
      DataTable dt1;
      string ErrMes;
      z.Sql2DTReadOnly(s1, out dt1, null, out ErrMes);
      TreeNode tnd;

      foreach (DataRow drx in dt1.Rows)
      {
        tnd = new TreeNode
        {
          id = drx["TableName"].ToString(),
          text = drx["title"].ToString(),
          Level = 1,
          iconCls = "table_6",
          state = drx["TableName"].ToString() + " OK",
          leaf = true
        };
        lstF.Add(tnd);
      }
      TreeNode root = new TreeNode
      {
        text = "基礎數據字典",
        expanded = false,
        iconCls = "folder_close",
        Level = 0,
        state = "RootOfTree",
        leaf = true
      };
      if (lstF.Count > 0)
      {
        root.expanded = true;
        root.leaf = false;
        root.iconCls = "folder_open";
        root.children = lstF;
      }

      string JsonStr;
      JsonStr = JsonConvert.SerializeObject(root);
      HttpResponseMessage response = Request.CreateResponse(HttpStatusCode.OK, "value");
      response.Content = new StringContent(JsonStr, Encoding.GetEncoding("UTF-8"), "application/json");
      response.Headers.CacheControl = new CacheControlHeaderValue()
      {
        MaxAge = TimeSpan.FromMinutes(10)
      };
      return response;
    }
  }

  internal class TreeNode
  {
    public string id { get; set; }
    public string text { get; set; }
    public string iconCls { get; set; }
    public string state { get; set; }
    public bool leaf { get; set; }
    public int Level { get; set; }
    public bool expanded { get; set; }
    public List<TreeNode> children { get; set; }
  }