关于ASP.NET中TreeView用法的一个小例子

using system;
using system.collections;
using system.configuration;
using system.data;
using system.web;
using system.web.security;
using system.web.ui;
using system.web.ui.htmlcontrols;
using system.web.ui.webcontrols;
using system.web.ui.webcontrols.webparts;
using system.data.sqlclient;
using common;
using dataaccess;

public partial class controls_producttype2 : system.web.ui.usercontrol
{

    producttype producttype = new producttype();
    product product = new product();

  protected void treeview_treenodepopulate(object sender, treenodeeventargs e)
    {

        if (e.node.childnodes.count == 0)
        {
            switch (e.node.depth)
            {
                case 0:
                    populatecategories(e.node);
                    break;
                case 1:
                    populateproducttype(e.node);
                    break;
                case 2:
                    populateproducts(e.node);
                    break;
            }
        }

      //  int i = treetoxml.treetoxml(treeview1, "d:/treetoxml.xml");

    }

    protected void page_load(object sender, eventargs e)
    {

    }

    //第一级节点（parentid=0）
    void populatecategories(treenode node)
    {
        datatable dt = new datatable();
        dt = producttype.getlistbyfathernode();

        if (dt.rows.count > 0)
        {
            foreach (datarow row in dt.rows)
            {
                treenode newnode = new treenode(row["producttypename"].tostring(), row["producttypeid"].tostring(),"","../webproductlist.aspx?producttypeidone="+ row["producttypeid"].tostring() +"","");
                newnode.populateondemand = true;
                newnode.selectaction = treenodeselectaction.expand;
                node.childnodes.add(newnode);
                node.expanded = true ;
            }
        }

    }

    //第二级节点
    void populateproducttype(treenode node)
    {
        datatable dt = new datatable();
        queryparam queryparam = new queryparam();
        queryparam.add("parentid", queryparam.relation.eq, "" + node.value + "");
        dt = producttype.getlistbybranchnode(queryparam);

        if (dt.rows.count > 0)
        {
            foreach (datarow row in dt.rows)
            {
                treenode newnode = new treenode(row["producttypename"].tostring(), row["producttypeid"].tostring(), "", "../webproductlist.aspx?producttypeidtwo=" + row["producttypeid"].tostring() + "", "");
                newnode.populateondemand = true;
                newnode.selectaction = treenodeselectaction.expand;
                node.childnodes.add(newnode);
                node.expanded = false ;
            }
        }
    }

    //第三个节点
    void populateproducts(treenode node)
    {
        datatable dt = new datatable();
        queryparam queryparam = new queryparam();
        queryparam.add("producttypeitemid", queryparam.relation.eq, "" + node.value + "");
        dt = product.getlist(queryparam);

        if (dt.rows.count > 0)
        {
            foreach (datarow row in dt.rows)
            {
                treenode newnode = new treenode(row["productname"].tostring(), row["productid"].tostring(), "", "../webproductdetaile.aspx?productid=" + row["productid"].tostring() + "", "");
                //newnode.populateondemand = false;
                //newnode.selectaction = treenodeselectaction.none;
                newnode.populateondemand =true ;
                newnode.selectaction = treenodeselectaction.expand ;
                node.childnodes.add(newnode);
                node.expanded = false;
            }
        }
    }

}