windows-phone-7 – ListBox数据虚拟化没有生效

我从xml获得了1000个项目并将它们加载到List对象中. List是数据绑定到ListBox,它是水平方向的,因此用户可以从左到右或从右到左翻阅项目.由于项目数量巨大,我的应用程序可能因内存使用过多而退出.如果我将项目减少到50就可以了.

我找到了这篇文章
http://shawnoster.com/blog/post/Improving-ListBox-Performance-in-Silverlight-for-Windows-Phone-7-Data-Virtualization.aspx

然后这篇关于数据虚拟化的文章

http://blogs.msdn.com/b/ptorr/archive/2010/08/16/virtualizing-data-in-windows-phone-7-silverlight-applications.aspx

在实现实现IList的虚拟化类之后,我发现没有区别.这个[](下面)被称为1000次,虽然我预计它只会被调用30-40次,因为我知道UI已经在Listbox中虚拟化了.为什么虚拟化没有开始？

object IList.this[int index]
{
    get
    {
        if (index >= cachedItems.Count)
        {
            //replenish cache code here
        }

        return cachedItems[index];
    }
    set
    {
        throw new NotImplementedException();
    }
}

这是与问题相关的XAML部分.希望这能够全面了解代码.不确定Width = Auto是否与它有关但我无法更改它,否则我的刷卡停止.

<ScrollViewer HorizontalScrollBarVisibility="Auto" Margin="0,0" Width="auto" x:Name="WordsScrollview" Opacity="1"  Grid.Row="1" RenderTransformOrigin="0.5,0.5">

    <ListBox x:Name="horizontalListBox" Width="auto" Height="Auto" >

        <ListBox.ItemsPanel>
            <ItemsPanelTemplate>
                <StackPanel Orientation="Horizontal">
                </StackPanel>
            </ItemsPanelTemplate>
        </ListBox.ItemsPanel>

        <ListBox.ItemTemplate>
            <DataTemplate>
                <StackPanel>
                    <TextBlock Width="430" Text="{Binding Word}"  TextWrapping="Wrap" Style="{StaticResource PhoneTextExtraLargeStyle}" TextAlignment="Center" />
                    <Image Height="290" HorizontalAlignment="Center" Name="image1" Stretch="Fill"  Width="430" Source="{Binding ImageFile}" Margin="10,50,10,0" />
                </StackPanel>
            </DataTemplate>
        </ListBox.ItemTemplate>

        <ListBox.Background>
            <SolidColorBrush />
        </ListBox.Background>

    </ListBox>

</ScrollViewer>

<ListBox x:Name="horizontalListBox"   Height="Auto" ScrollViewer.HorizontalScrollBarVisibility="Auto" >

                <ListBox.ItemsPanel>
                    <ItemsPanelTemplate>
                        <VirtualizingStackPanel Orientation="Horizontal">

                        </VirtualizingStackPanel>
                    </ItemsPanelTemplate>
                </ListBox.ItemsPanel>
                <ListBox.ItemTemplate>
                    <DataTemplate>

                            <StackPanel>
                                <TextBlock Width="430" Text="{Binding Word}"  TextWrapping="Wrap" Style="{StaticResource PhoneTextExtraLargeStyle}" TextAlignment="Center" />

                                <Image Height="290" HorizontalAlignment="Center" Name="image1" Stretch="Fill"  Width="430" Source="{Binding ImageFile}" Margin="10,0" />
                               </StackPanel>

                    </DataTemplate>
                </ListBox.ItemTemplate>
                <ListBox.Background>
                    <SolidColorBrush />
                </ListBox.Background>
            </ListBox>