我使用代碼使得TreeView控件全部展開if (treeView1.SelectedNode.Index==0)                        {                            if (i == 0)                            {                                this.treeView1.CollapseAll();                                                                i = 1;                            }                            else                            {                                this.treeView1.ExpandAll();                                i = 0;                            }                         } 展開后，滾動條自動滾動到最下邊。如何讓滾動條滾動到最上邊。并選中下一個同級菜單。