ListBox ScrollIntoView无法在NavigateTo上工作

本文关键字:NavigateTo 工作 ScrollIntoView ListBox | 更新日期: 2023-09-27 18:28:45

我正在制作一个时间可调的计时器。出于这个原因,我想使用列表框设置时间(一个用于分钟,一个用于秒)。列表框的填充是使用以下代码完成的。

public EditTime()
    {
        this.InitializeComponent();
        List<Numbers> numbers = new List<Numbers>();
        for (int i = 0; i < 61; i++)
        {
            numbers.Add(new Numbers() { Number = i });
        }
        listBoxobjM.ItemsSource = numbers;
        listBoxobjS.ItemsSource = numbers;

        this.navigationHelper = new NavigationHelper(this);
        this.navigationHelper.LoadState += this.NavigationHelper_LoadState;
        this.navigationHelper.SaveState += this.NavigationHelper_SaveState;
    }
    public class Numbers
    {
        public int Number { get; set; }
    }

在XAML中,我有以下ListBoxes代码:

<Grid Grid.Row="1" x:Name="ContentRootM" Margin="65,0,0,0" Width="130">
            <ListBox Background="Transparent"  Margin="10,10,10,10"  BorderThickness="2" MaxHeight="580" Grid.Row="2" x:Name="listBoxobjM" VerticalContentAlignment="Top" HorizontalContentAlignment="Center">
                <ListBox.ItemTemplate>
                    <DataTemplate>
                        <Border Margin="5" BorderBrush="{ThemeResource ApplicationHeaderForegroundThemeBrush}" BorderThickness="1" Background="{ThemeResource ButtonBackgroundThemeBrush}">
                            <TextBlock  TextAlignment="Left"  HorizontalAlignment="Left"  Width="70" Height="80" x:Name="LbM" Text="{Binding Number}" FontSize="48" Foreground="{ThemeResource ButtonForegroundThemeBrush}"  />
                        </Border>
                    </DataTemplate>
                </ListBox.ItemTemplate>
            </ListBox>
        </Grid>
        <Grid Grid.Row="1" x:Name="ContentRootS" Margin="10,0,0,0" Width="130">
            <ListBox Background="Transparent"  Margin="10,10,10,10" Height="auto" BorderThickness="2" MaxHeight="580" Grid.Row="2" x:Name="listBoxobjS" VerticalContentAlignment="Top" HorizontalContentAlignment="Center">
                <ListBox.ItemTemplate>
                    <DataTemplate>
                        <Border Margin="5" BorderBrush="{ThemeResource ApplicationHeaderForegroundThemeBrush}" BorderThickness="1" Background="{ThemeResource ButtonBackgroundThemeBrush}">
                            <StackPanel Width="125" Orientation="Horizontal" Grid.Row="1">
                                <TextBlock  TextAlignment="Left"  HorizontalAlignment="Left"  Width="70" Height="80" x:Name="LbS" Text="{Binding Number}" TextWrapping="Wrap" FontSize="48" Foreground="{ThemeResource ButtonForegroundThemeBrush}"  />
                            </StackPanel>
                        </Border>
                    </DataTemplate>
                </ListBox.ItemTemplate>
            </ListBox>
        </Grid>

当我导航到此页面时,我可以使用listBoxobjM.SelectedIndex=I选择预选时间(分钟和秒);在以下代码中。我可以手动滚动到此项目,并看到它已被选中。

protected override void OnNavigatedTo(NavigationEventArgs e)
    {
        this.navigationHelper.OnNavigatedTo(e);
        string parameter = e.Parameter as string;
        string[] parts = parameter.Split(';');
        id = int.Parse(parts[0]);
        ....
        DatabaseHelper fetch = new DatabaseHelper();
        TeamType team = fetch.GetTeamType(id);
        for (int i = 0; i < 60; i++)
        {
            if (i == team.PlayTime.Minutes)
            {
                listBoxobjM.SelectedIndex = i;
                listBoxobjM.ScrollIntoView(listBoxobjM.SelectedIndex);
           }
            if (i == team.PlayTime.Seconds)
            {
                listBoxobjS.SelectedIndex = i;
                listBoxobjS.ScrollIntoView(listBoxobjS.SelectedIndex);
            }
        }
    }

我希望列表框自动滚动到SelectedIndex,但列表框显示顶部的第一个项目。如何确保ListBox滚动到SelectedIndex?

ListBox ScrollIntoView无法在NavigateTo上工作

ListBox.ScrollIntoView()接受ListBox中的项,而不是索引。(MSDN文档)所以不是

listBoxobjM.ScrollIntoView(listBoxobjM.SelectedIndex);

尝试

listBoxobjM.ScrollIntoView(listBoxobjM.SelectedItem);

相反。

最终,我通过另一个Stack Overflow问题自己找到了解决方案。在这里,他们也遇到了ListView的问题,因为它充满了延迟。使用awaitTask.Delay(请参阅代码)可以解决问题。我感谢大家的贡献。

for (int i = 0; i < 60; i++)
        {
            if (i == team.PlayTime.Minutes)
            {
                listBoxobjM.SelectedIndex = i;
                await Task.Delay(1000);
                listBoxobjM.ScrollIntoView(listBoxobjM.SelectedItem);
            }
            if (i == team.PlayTime.Seconds)
            {
                listBoxobjS.SelectedIndex = i;
                await Task.Delay(1000);
                listBoxobjS.ScrollIntoView(listBoxobjS.SelectedItem);
            }
        }