UWP可拖动矩形画布，只能沿着对角线旅行

Question

Good Afternoon Folks，希望有人可以帮我一把。

新编码所以正在开展一个侧面项目，让我保持活跃。然而，在Stackoverflow上发现了这篇文章，它有我需要的功能

How can I make a Rectangle on a canvas which is draggable?

MouseLeftButtonDown不可用，它是否已在Blank UwP项目中被取代？所以我修改了它如下。

然而，矩形只能在一个方向上来回对角移动。

我错过了什么。

 public sealed partial class MainPage : Page
{
    bool drag = false;
    Windows.UI.Input.PointerPoint startPoint;
    public MainPage()
    {
        this.InitializeComponent();
    }

    private void mnuGas1_Click(object sender, RoutedEventArgs e)
    {

        var cargo = new Rectangle();
        //Properties
        cargo.Height = 100;
        cargo.Width = 100;
        cargo.Fill = new SolidColorBrush(Windows.UI.Colors.HotPink);
        //Handlers
        cargo.PointerPressed += Cargo_PointerPressed;
        cargo.PointerMoved += Cargo_PointerMoved;
        cargo.PointerReleased += Cargo_PointerReleased;
        Canvas.SetLeft(cargo, 0);
        Canvas.SetTop(cargo, 0);
        containerContainer.Children.Add(cargo);
    }

    private void Cargo_PointerReleased(object sender, PointerRoutedEventArgs e)
    {
        drag = false;
        //throw new NotImplementedException();
    }

    private void Cargo_PointerMoved(object sender, PointerRoutedEventArgs e)
    {

       if (drag)
        {
           Rectangle cargoDrag = sender as Rectangle;
            Windows.UI.Input.PointerPoint newPoint = e.GetCurrentPoint(containerContainer);
           var left = Canvas.GetLeft(cargoDrag);
          var top = Canvas.GetLeft(cargoDrag);
            Canvas.SetLeft(cargoDrag, left + (newPoint.RawPosition.X - startPoint.RawPosition.X));
            Canvas.SetTop(cargoDrag, top + (newPoint.RawPosition.Y - startPoint.RawPosition.Y));
            startPoint = newPoint;
        }
        //throw new NotImplementedException();
    }

    private void Cargo_PointerPressed(object sender, PointerRoutedEventArgs e)
    {

        drag = true;
        startPoint = e.GetCurrentPoint(containerContainer);
        log.Text = "Clicked";

        //throw new System.NotImplementedException();

    }



}

}

enter<Page
x:Class="App2.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:App2"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">


<Grid Background="AntiqueWhite" VerticalAlignment="Center">
    <Grid.RowDefinitions>
        <RowDefinition Height="Auto"/>
        <RowDefinition Height="Auto"/>
        <RowDefinition Height="Auto"/>
    </Grid.RowDefinitions>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="Auto"/>
        <ColumnDefinition/>
    </Grid.ColumnDefinitions>
    <Image Source="Assets/PrinceDeck.png" Grid.Row="1" Grid.Column="0" MaxWidth="1250"></Image>
    <Canvas Name="containerContainer" Grid.Row="1" Grid.Column="0" MaxWidth="1250"  Canvas.Left="0" Canvas.Top="0" ></Canvas>
    <Rectangle Fill="LightBlue" Grid.Column="0" Grid.Row="0" Height="300"/>
    <Rectangle Fill="LightBlue" Grid.Column="0" Grid.Row="2" Height="300"/>

    <Rectangle Fill="Pink" Grid.Row="1" Grid.Column="1" Height="Auto"/>
    <Rectangle Fill="CornflowerBlue" Grid.Column="1" Grid.Row="0" Height="300"/>
    <Rectangle Fill="CornflowerBlue" Grid.Column="1" Grid.Row="2" Height="300"/>
    <StackPanel  Grid.Column="1" Grid.Row="1" >
        <Button Content="Cargo Boxes" Width="Auto"></Button>
        <Button Content="Cargo Baskets" Width="Auto"></Button>
        <Button Content="Chemical Tanks" Width="Auto"></Button>
        <Button Content="Closed Mud Skips" Width="Auto"></Button>
        <Button Content="Dry Goods Container" Width="Auto"></Button>
        <Button Content="Drum Baskets" Width="Auto"></Button>
        <Button Content="FIBC Containers" Width="Auto"></Button>
        <Button Content="Gas Racks" Width="Auto">
            <Button.Flyout>
                <MenuFlyout>
                    <MenuFlyoutItem Name="mnuGas1" Text="1150mm" Click="mnuGas1_Click"/>
                    <MenuFlyoutItem Text="1462mm"/>
                </MenuFlyout>
            </Button.Flyout>
        </Button>
        <Button Content="Helifuel Tanks" Width="Auto"></Button>
        <Button Content="Half Heights" Width="Auto"></Button>
        <Button Content="Lifting Frames" Width="Auto"></Button>
        <Button Content="Mini Containers" Width="Auto"></Button>
        <Button Content="Open Tops" Width="Auto"></Button>
        <Button Content="Pipe Baskets" Width="Auto"></Button>
        <Button Content="Tubular Transportation Frames" Width="Auto"></Button>
        <TextBlock Name="log" Grid.Column="0" Grid.Row="2" Height="300"/>

    </StackPanel>



</Grid>

代码