Question

我遇到了与Windows Phone 8的RadDataBoundListBox命令绑定的事件的问题。

我有以下XAML：

<Grid x:Name="LayoutRoot" Background="{StaticResource PivotBackground}" DataContext="{Binding RecomandationViewModel, Source={StaticResource Locator}}">
    ..........
                <telerikPrimitives:RadDataBoundListBox x:Name="DataBoundListBox" ItemsSource="{Binding RecommendedSongs}" DisplayMemberPath="Name" EmptyContent=" " DataVirtualizationMode="OnDemandAutomatic">
                    <i:Interaction.Triggers>
                        <i:EventTrigger EventName="DataRequested">
                           <command:EventToCommand Command="{Binding DataRequestedCommand}"/>
                       </i:EventTrigger>
                    </i:Interaction.Triggers>
                <telerikPrimitives:RadDataBoundListBox.ItemLoadingTemplate>
                    <DataTemplate>
                        <bitrimitives:BitBusyIndicator IsRunning="True" AnimationStyle="AnimationStyle9" Foreground="{StaticResource MyColor}" Content=""/>
                    </DataTemplate>
                </telerikPrimitives:RadDataBoundListBox.ItemLoadingTemplate>
                    </telerikPrimitives:RadDataBoundListBox>
            </Grid>

视图模型代码：

private RelayCommand _dataRequestedCommand;
    public RelayCommand DataRequestedCommand
    {
        get
        {
            if (_dataRequestedCommand == null)
            {
                _dataRequestedCommand = new RelayCommand(DataRequested, () => true);
            }
            return _dataRequestedCommand;
        }
    }
private void DataRequested()
    {
        int i = 4;
    }

DataRequested方法永远不会被触发，但如果我订阅RadDataBoundListBox的DataRequested事件，则会触发该方法。你能帮我解决这个问题吗？

Answer 1

看看这个link。也许它可以帮助你。

OnDemandAutomatic虚拟化模式是一种模式，在最终用户接近可滚动列表末尾时自动请求数据项。通过使用RadDataBoundListBox公开的ItemLoadingContent和ItemLoadingTemplate属性，可以显示指示正在处理数据请求的专用可视容器。定义ItemLoadingTemplate的可能方法如下所示：

<telerikPrimitives:RadDataBoundListBox.ItemLoadingTemplate>
    <DataTemplate>
        <Grid MinHeight="14">
            <Grid.Triggers>
                <EventTrigger>
                    <BeginStoryboard>
                        <Storyboard>
                            <DoubleAnimation Storyboard.TargetName="ellipseTranslate" RepeatBehavior="Forever">
                                <DoubleAnimation.EasingFunction>
                                    <SineEase EasingMode="EaseInOut" />
                                </DoubleAnimation.EasingFunction>
                            </DoubleAnimation>
                        </Storyboard>
                    </BeginStoryboard>
                </EventTrigger>
            </Grid.Triggers>
            <Ellipse VerticalAlignment="Center" HorizontalAlignment="Left" Width="6" Height="6" Grid.Column="1" Fill="{StaticResource PhoneAccentBrush}">
                <Ellipse.RenderTransform>
                    <TranslateTransform x:Name="ellipseTranslate" X="0" />
                </Ellipse.RenderTransform>
            </Ellipse>
        </Grid>
    </DataTemplate>
</telerikPrimitives:RadDataBoundListBox.ItemLoadingTemplate>

要使用OnDemandAutomatic虚拟化模式，只需将RadDataBoundListBox控件的DataVirtualizationMode属性设置为DataVirtualizationMode.OnDemandAutomatic。您还需要处理DataRequested事件，该事件将在需要加载更多数据时触发：

public MainPage()
{
    InitializeComponent();

    this.radDataBoundListBox.DataVirtualizationMode = DataVirtualizationMode.OnDemandAutomatic;

    this.radDataBoundListBox.DataRequested += this.OnDataRequested;
}

private void OnDataRequested(object sender, EventArgs args)
{
    //TODO: download data items
}

RadDataBoundListBox事件命令未触发

1 个答案: