RadTreeView按需加载

XML：

.....

LoadOnDemand="ExplorerTreeView_LoadOnDemand"

>

 

后台代码：

private void ExplorerTreeView_LoadOnDemand(object sender, Telerik.Windows.RadRoutedEventArgs e)
        {
            RadTreeViewItem item = e.OriginalSource as RadTreeViewItem;            
            if (item.Item is VoyageVO)
            {
                var voyage = item.Item as VoyageVO;                
                ObservableCollection<LegVO> Legs = new ObservableCollection<LegVO>();

                if (item != null && item.Items.Count < 1)
                {
                    Task.Factory.StartNew(() =>
                    {
                        Legs = _IndoorSampleCheckHttpProxy.GetLegsByVoyageID(voyage.ID);
                        if (Legs == null) return;
                        //voyage.Legs.AddRange(Legs);
                        Application.Current.Dispatcher.Invoke(new Action(delegate()
                        {
                        item.ItemsSource = Legs;
                        }));
                    })
                    .ContinueWith((t) =>
                    {                        
                        Application.Current.Dispatcher.Invoke(new Action(delegate()
                        {
                            if (Legs.Count == 0)
                                item.IsLoadOnDemandEnabled = false;                                
                            else
                                item.IsLoadingOnDemand = false;
                        }));
                    });
                }
            }
            else if (item.Item is LegVO)
            {
                var leg = item.Item as LegVO;
                ObservableCollection<StationVO> Stations = new ObservableCollection<StationVO>();
                if (item != null && item.Items.Count < 1)
                {
                    StationQueryInformation stationQueryInformation = new StationQueryInformation();
                    stationQueryInformation.LegID = leg.ID;
                    Task.Factory.StartNew(() =>
                    {
                        Stations = _IndoorSampleCheckHttpProxy.GetStationsByLeg(stationQueryInformation);
                        //leg.Stations.AddRange(Stations);
                        Application.Current.Dispatcher.Invoke(new Action(delegate()
                        {
                            item.ItemsSource = Stations;
                        }));
                    })
                    .ContinueWith((t) =>
                    {
                        item.Dispatcher.Invoke(new Action(delegate()
                        {
                            if (Stations.Count == 0)
                                item.IsLoadOnDemandEnabled = false;
                            else
                                item.IsLoadingOnDemand = false;
                        }));
                    });
                }
            }
        }

标记部分为：两种操作都能达到目的，前一种会造成TreeViewItem“多选”，显示效果较差。