treeview的节点的展开和收缩

public void Expandnodes(Microsoft.Web.UI.WebControls.TreeNode node,bool Expand)
{
    foreach(Microsoft.Web.UI.WebControls.TreeNode n in node.Nodes)
    {
 if(n.Nodes.Count>0)
 {
     n.Expanded = Expand;
     Expandnodes(n, Expand);
 }
     }
}
public void Expandnodes(Microsoft.Web.UI.WebControls.TreeView treeview, bool Expand)
{
 foreach(Microsoft.Web.UI.WebControls.TreeNode n in treeview.Nodes)
 {
                if(n.Nodes.Count>0)
        {
  n.Expanded = Expand;
  Expandnodes(n, Expand);
        }
 }
}

Expandnodes(Me.TreeView1, true)展开全部节点，Expandnodes(Me.TreeView1, false)折叠全部节点