Question

我的FlipView中有一个MainPage。它是ItemTemplate绑定到名为UserControl的{{1}}。它是landscapeControl绑定到名为ItemsSource的类的列表。

landscapeControl：

MyLandscape

<Grid> <ScrollViewer x:Name="LScrollViewer" MaxZoomFactor="2.0" MinZoomFactor="1.0" HorizontalScrollBarVisibility="Hidden" VerticalScrollBarVisibility="Hidden" DoubleTapped="LScrollViewer_DoubleTapped" > <Canvas x:Name="inkCanvas" Background="Transparent"> <StackPanel x:Name="LStackPanel" Orientation="Horizontal" Margin="0,0,0,0"> <Image x:Name="LImage0" HorizontalAlignment="Right" Source="{Binding firstImage}" Width="570"/> <Image x:Name="LImage1" HorizontalAlignment="Left" Source="{Binding nextImage}" Width="570"/> </StackPanel> </Canvas> </ScrollViewer> </Grid>上课：

MyLandscape

我的照片完美呈现。我想要的就是三件事：

1）我想从我的public class MyLandscape { public ImageSource firstImage { get; set; } public ImageSource nextImage { get; set; } public Canvas inkCanvas { get; set; } }访问我的Canvas。我想在MainPage事件中执行此操作：

flipView_SelectionChanged

但是pc变量总是为空！我想绑定landscapeControl pc = flipView1.SelectedItem as landscapeControl; if (flipView1.Items.Count > 0) { var myCanvas = pc.getCanvas(); m_CanvasManager = new CanvasManager(myCanvas); }，所以每两张图片都有一个Canvas？那可能吗？

Answer 1

一种方法是使用Command将UIElement传递回您的模型。

基本上，您的inkCanvas元素将附加CanvasLoadedCommand这样的附加内容。请注意，只有在inkCanvas完全加载时才会调用此命令。

    <Canvas x:Name="inkCanvas" Background="Transparent">
        <Interactivity:Interaction.Behaviors>
            <Core:EventTriggerBehavior>
                <Core:InvokeCommandAction Command="{Binding CanvasLoadedCommand}" CommandParameter="{Binding ElementName=inkCanvas}" />
            </Core:EventTriggerBehavior>
        </Interactivity:Interaction.Behaviors>

我在这里为这个小demo（工作源代码）创建了一个简单的DelegateCommand。加载inkCanvas时，

this.inkCanvas =（Canvas）canvas;

将被调用，然后inkCanvas属性将被填充。

    private DelegateCommand _canvasLoadedCommand;
    public DelegateCommand CanvasLoadedCommand
    {
        get
        {
            if (_canvasLoadedCommand == null)
            {
                _canvasLoadedCommand = new DelegateCommand((canvas) =>
                {
                    this.inkCanvas = (Canvas)canvas;
                }, 
                (canvas) => canvas != null);
            }

            return _canvasLoadedCommand;
        }
    }

希望这有帮助！

Answer 2

更改您的代码：

if (flipView1.Items.Count > 0) { 
    var myCanvas = pc.getCanvas(); 
    m_CanvasManager = new CanvasManager(myCanvas);
}

到

if (e.AddedItems.Count > 0) { 
    var myCanvas = (e.AddedItems[0] as LandscapeControl).getCanvas(); 
    m_CanvasManager = new CanvasManager(myCanvas); 
}

Answer 3

嗯，经过长时间的搜索，在Windows Store Apps：我们无法访问Canvas内的FlipView，如果它直接位于FlipView内DataTemplate或FlipView的{{1}}。

从MainPage访问UserControl中ItemsSource内的Canvas

3 个答案: