Win 8中WPF listview与listBox的Drag、Drop操作

<UserControl x:Class="DragTitleToWebView.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
d:DesignHeight="768" d:DesignWidth="1366">

<Grid x:Name="LayoutRoot" Background="#FF0C0C0C">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="1*"/>
<ColumnDefinition Width="5*"/>
</Grid.ColumnDefinitions>
<ListView Grid.Column="0" AllowDrop="True" CanDragItems="True"  CanReorderItems="True" DragItemsStarting="ListView_DragItemsStarting" >
<ListView.Resources>
<Style TargetType="Rectangle">
<Setter Property="Width" Value="100"/>
<Setter Property="Height" Value="100"/>
</Style>
</ListView.Resources>
<Rectangle Fill="Orange"  Tag="Rect1" Width="100" Height="100"/>
<Rectangle Fill="Orange" Tag="Rect2" Width="120" Height="120"/>
<Rectangle Fill="Orange" Tag="Rect3" Width="140" Height="140"/>
<Rectangle Fill="Orange" Tag="Rect4" Width="160" Height="160"/>
</ListView>
<ListBox x:Name="lb" Grid.Column="1" Margin="10">

</ListBox>
<Rectangle  Margin="10" x:Name="droppanel" Opacity="0.01" Visibility="Collapsed" Grid.Column="1" AllowDrop="True" Drop="droppanel_Drop" Fill="Green"/>
</Grid>

</UserControl>

using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Shapes;
partial class MainPage
{
private bool flag = false;
public MainPage()
{
InitializeComponent();
}

private void ListView_DragItemsStarting(object sender, DragItemsStartingEventArgs e)
{
e.Data.SetText("t", (e.Items[0] as Rectangle).Tag.ToString());
e.Data.SetText("width", (e.Items[0] as Rectangle).Width.ToString());
e.Data.SetText("height", (e.Items[0] as Rectangle).Height.ToString());

droppanel.Visibility = Windows.UI.Xaml.Visibility.Visible;
lb.Visibility = Windows.UI.Xaml.Visibility.Collapsed;
if (flag)
{
lb.Visibility = Windows.UI.Xaml.Visibility.Visible;
}
}

private void droppanel_Drop(object sender, DragEventArgs e)
{
string tag = e.Data.GetText("t");
//如果已经有相同的item，则返回
foreach (Rectangle item in lb.Items)
{
if (item.Tag.ToString() == tag)
{
return;
}
}
int width = int.Parse(e.Data.GetText("width"));
int height = int.Parse(e.Data.GetText("height"));
Rectangle rect = new Rectangle();
rect.Tag = tag;
rect.Height = height;
rect.Width = width;
SolidColorBrush b = new SolidColorBrush(Colors.Orange);
rect.Fill = b;

lb.Items.Add(rect);

droppanel.Visibility = Windows.UI.Xaml.Visibility.Collapsed;
lb.Visibility = Windows.UI.Xaml.Visibility.Visible;

flag = true;
}
}