我使用代码使得TreeView控件全部展开

if (treeView1.SelectedNode.Index==0)
                        {
                            if (i == 0)
                            {
                                this.treeView1.CollapseAll();
                               
                                i = 1;
                            }
                            else
                            {
                                this.treeView1.ExpandAll();
                                i = 0;
                            }
                        }

展开后，滚动条自动滚动到最下边。如何让滚动条滚动到最上边。并选中下一个同级菜单。