Question

我正在开发一个WP8应用程序，我正在尝试使用LongListSelector（作为People应用程序）在JumpList中显示所有用户联系人。

它工作正常，但根据联系人的数量，用户界面需要很长时间才能显示。

我这样做：

XAML：

<DataTemplate x:Key="AddrBookItemTemplate" >
    <ListBoxItem>
        <StackPanel VerticalAlignment="Top" >
            <Border Height="62" Width="62">
                <Image Source="{Binding Path=Image}" Width="62" Height="62" Stretch="Fill" />                        
            </Border>
            <TextBlock Text="{Binding Path=Name, Mode=OneWay}" />
        </StackPanel>
    </ListBoxItem>
</DataTemplate>

<DataTemplate x:Key="AddrBookGroupHeaderTemplate">
    <Border Background="Transparent" Margin="0,5,0,0">
        <Border Width="62" Height="62" >
            <TextBlock Text="{Binding Key}" FontFamily="{StaticResource PhoneFontFamilySemiLight}" />
        </Border>
    </Border>
</DataTemplate>

<phone:JumpListItemBackgroundConverter x:Key="BackgroundConverter" Enabled="#FF03A9F4"/>
<phone:JumpListItemForegroundConverter x:Key="ForegroundConverter"/>

<Style x:Key="AddrBookJumpListStyle" TargetType="phone:LongListSelector">
    <Setter Property="GridCellSize"  Value="113,113"/>
    <Setter Property="LayoutMode" Value="Grid" />
    <Setter Property="ItemTemplate">
        <Setter.Value>
            <DataTemplate>
                <Border Background="{Binding Converter={StaticResource BackgroundConverter}}" Width="113" Height="113" Margin="6" >
                    <TextBlock Text="{Binding Key}" FontFamily="{StaticResource PhoneFontFamilySemiBold}" FontSize="48" Padding="6" 
               Foreground="{Binding Converter={StaticResource ForegroundConverter}}" VerticalAlignment="Center"/>
                </Border>
            </DataTemplate>
        </Setter.Value>
    </Setter>
</Style>

<Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,10,12,10">
    <phone:LongListSelector
        x:Name="AddrBook"
        JumpListStyle="{StaticResource AddrBookJumpListStyle}"
        Background="Transparent"
        GroupHeaderTemplate="{StaticResource AddrBookGroupHeaderTemplate}"
        ItemTemplate="{StaticResource AddrBookItemTemplate}"
        LayoutMode="List"
        IsGroupingEnabled="true"
        HideEmptyGroups ="true"
        SelectionChanged="AddrBook_SelectionChanged"/>
</Grid>

代码：

private void Contacts_SearchContactsCompleted(object sender, ContactsSearchEventArgs e)
{
    Stopwatch stopwatch = Stopwatch.StartNew();

    IList<Contact> contacList = e.Results.Where(m => m.PhoneNumbers.Count() > 0).ToList();
    cdList = new List<ContactData>();

    foreach(Contact c in contacList)
    {
        BitmapImage img = new BitmapImage();
        img.DecodePixelHeight = 62;
        img.DecodePixelWidth = 62;
        img.UriSource = null;

        bool tam = c.GetPicture() == null;

        if (!tam)
            img.SetSource(c.GetPicture());

        foreach (ContactPhoneNumber cpn in c.PhoneNumbers)
        {
            ContactData cd = new ContactData();
            cd.Name = c.DisplayName;
            cd.Image = img;
            cdList.Add(cd);
        }
    }

    List<AlphaKeyGroup<ContactData>> DataSource = AlphaKeyGroup<ContactData>.CreateGroups(cdList,
                            System.Threading.Thread.CurrentThread.CurrentUICulture,
                        (ContactData s) => { return s.Name; }, true);
    AddrBook.ItemsSource = DataSource;

    cdListFiltred = cdList;

    stopwatch.Stop();
    System.Diagnostics.Debug.WriteLine("Time elapsed: {0}", stopwatch.Elapsed);
}

我试图用这个“秒表”测量时间，以验证代码是否是问题，但它返回“Time elapsed：00：00：00.3080245”，并且联系人在视觉上花费的时间比这更多出现在用户界面上。

然后，是XAML的问题？如何更快地显示此列表？

修改

我在这里上传了我的代码，如果能提供帮助：https://www.dropbox.com/s/k9c63xgi0wbf6r6/ContactsInJumpList.rar?dl=0

Answer 1

问题在于XAML。当数据量很大时，性能很差。您可以使用虚拟化来提高性能，快速谷歌搜索虚拟化longlistselector应该会给你带来结果。我建议使用Telerik控件来处理大量数据，因为控件本身是虚拟化的。

UI需要很长时间才能在JumpListSelector（WP8）中显示用户联系人列表 - 如何改善这段时间？

1 个答案: