WPF中的TreeView

                   <treeview x:name="chaptertree"  grid.column="0"  selecteditemchanged="chaptertree_selecteditemchanged" previewmouserightbuttondown="chaptertree_previewmouserightbuttondown" fontsize="14"  itemssource="{binding path=nodes}" >
                       
                        <treeview.contextmenu>
                            <contextmenu>
                                <menuitem header="保存" name="btnalterdata" click="btnalterdata_click" />
                                <menuitem header="新增兄弟节点" name="btnsavedata" click="btnsavedata_click"/>
                                <menuitem header="新增子节点" name="btnsavesondata" click="btnsavesondata_click"/>
                                <menuitem header="删除" name="btnddeletedata" click="btnddeletedata_click"/>
                                <menuitem header="上移一位" name="btnup" click="btnup_click"/>
                                <menuitem header="下移一位" name="btndown" click="btndown_click"/>
                            </contextmenu>
                        </treeview.contextmenu>
                        <treeview.itemtemplate>
                            <hierarchicaldatatemplate datatype="{x:type c:ordermodel}" itemssource="{binding path=childnodes}">
                                <label content="{binding path=ordername}"/>
                            </hierarchicaldatatemplate>
                        </treeview.itemtemplate>
                    </treeview>

        commandmodel cm;

        public command()
        {
            initializecomponent();
            cm = new commandmodel();
            chaptertree.itemssource = cm.nodes;

        }

        public event propertychangedeventhandler propertychanged;
        private observablecollection<ordermodel> nodes = new observablecollection<ordermodel>();
        public observablecollection<ordermodel> nodes
        {
            get { return nodes; }
            set
            {
                nodes = value;
                if (propertychanged != null)
                    propertychanged(this, new propertychangedeventargs("nodes"));
            }
        }
        
        public commandmodel()
        {
            initiate();
        }
        private void initiate()
        {
            using (sqliteconnection con = new sqliteconnection(mainwindow.sb.tostring()))
            {
                datatable table = new datatable("mytable");
                var reader = con.executereader("select * from orderdata order by orderid");
                table.load(reader);
                observablecollection<ordermodel> _nodes = new observablecollection<ordermodel>();
                _nodes = converttolist(table);

                //showtreeview();
                nodes = getchildnodes(0, _nodes);

            }
        }

        private observablecollection<ordermodel> getchildnodes(long parentid, observablecollection<ordermodel> nodes)
        {
            list<ordermodel> a = new list<ordermodel>(nodes.where(x => x.parentid == parentid).tolist());
            observablecollection<ordermodel> mainnodes =new observablecollection<ordermodel>(a);
            list<ordermodel> b = new list<ordermodel>(nodes.where(x => x.parentid != parentid).tolist());
            observablecollection<ordermodel> othernodes =new observablecollection<ordermodel>(b);
            foreach (ordermodel node in mainnodes)
                node.childnodes = getchildnodes(node.id, othernodes);
            return mainnodes;
        }




        #region    datatable转list

        /// <summary>
        /// datatable转list
        /// </summary>
        /// <param name="dt"></param>
        /// <returns></returns>
        public static observablecollection<ordermodel> converttolist(datatable dt)
        {

            // 定义集合
            observablecollection<ordermodel> ts = new observablecollection<ordermodel>();

            // 获得此模型的类型
            type type = typeof(ordermodel);
            //定义一个临时变量
            string tempname = string.empty;
            //遍历datatable中所有的数据行
            foreach (datarow dr in dt.rows)
            {
                ordermodel t = new ordermodel();
                // 获得此模型的公共属性
                propertyinfo[] propertys = t.gettype().getproperties();
                //遍历该对象的所有属性
                foreach (propertyinfo pi in propertys)
                {
                    tempname = pi.name;//将属性名称赋值给临时变量
                    //检查datatable是否包含此列（列名==对象的属性名）  
                    if (dt.columns.contains(tempname))
                    {
                        // 判断此属性是否有setter
                        if (!pi.canwrite) continue;//该属性不可写，直接跳出
                        //取值
                        object value = dr[tempname];
                        //如果非空，则赋给对象的属性
                        if (value != dbnull.value)
                            pi.setvalue(t, value, null);
                    }
                }
                //对象添加到泛型集合中
                ts.add(t);
            }

            return ts;
        }

        #endregion

        public observablecollection<ordermodel> childnodes { get; set; }
        public ordermodel()
        {
            childnodes = new observablecollection<ordermodel>();
        }