C#异步Tree

 private void Tree_AfterExpand(object sender, TreeViewEventArgs e)
        {
            int FileID = int.Parse(((ListItem)comboxFile.Items[comboxFile.SelectedIndex]).ID);
            BackgroundWorker bw = new BackgroundWorker();
            bw.DoWork += new DoWorkEventHandler(bw_DoWork);
            bw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bw_RunWorkerCompleted);

            object[] oArgs = new object[] { e.Node, FileID };
            bw.RunWorkerAsync(oArgs);
            bomTree.SelectedNode = e.Node;
        }

  private void bw_DoWork(object sender, DoWorkEventArgs e)

        {
            object[] oArgs = e.Argument as object[];
            TreeNode tn = oArgs[0] as TreeNode;
            int FileID = int.Parse(oArgs[1].ToString());
            DataAccess da = new DataAccess();
            DataTable dtChildren = null;
            DataTable dgvlist = null;
            if (tn.Tag != null)
            {
                dtChildren = new DataTable();
                dtChildren = GetData();
                dgvlist = new DataTable();
                dgvlist =GetData(); 
            }
            else
            {
                dtChildren = new DataTable();
                dtChildren =da.SearchChildren(FileID, tn.Text + "%");
            }

            e.Result = new object[] { tn, dtChildren, dgvlist };
        }

 private void bw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            object[] oResult = e.Result as object[];
            TreeNode tNodeParent = oResult[0] as TreeNode;
            DataTable dtChildren = oResult[1] as DataTable;
            DataTable dgvlist = oResult[2] as DataTable;
            ArrayList arr = new ArrayList();
            
           
            //dosomething

        }