Question

当测试具有100000个项目的简单ListView时，ListView开始与其下方的项目重叠。有办法解决吗？

  <Grid>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="Auto"/>
        <ColumnDefinition Width="*"/>
    </Grid.ColumnDefinitions>
    <Grid.RowDefinitions>
        <RowDefinition Height="auto"/>
        <RowDefinition Height="500"/>
        <RowDefinition Height="50"/>
    </Grid.RowDefinitions>

    <TextBlock Grid.Row="0" Grid.Column="0" Margin="10,10,10,10" x:Name="pageTitle" Text="Page 1" />
    <ListView  Grid.Row="1" Grid.Column="1" Margin="10,10,10,10" x:Name="itemListView" ItemsSource="{x:Bind Items}"/>
    <TextBlock Grid.Row="2" Grid.Column="1" Margin="10,10,10,10" Text="Bottom Text" />
</Grid>

背后的代码：

    private ObservableCollection<string> _items = new ObservableCollection<string>();

    public ObservableCollection<string> Items
    {
        get { return this._items; }
    }

    protected override void OnNavigatedTo(NavigationEventArgs e)
    {
        base.OnNavigatedTo(e);
        FillItems();
    }

    private void FillItems()
    {
        for (int i = 0; i < 100000; i++)
        {
            Items.Add($"Item {i}");
        }
    }

Answer 1

同时加载所有元素会导致性能问题。您可以使用增量加载随着滚动条的进度加载元素。通过实现IIncrementalSource。您可以设置可以携带多少物品

每次视图需要调用GetPagedItemsAsync方法时显示更多项目。

public async Task<IEnumerable<Person>> GetPagedItemsAsync(int pageIndex, int pageSize)
    {
        // Gets items from the collection according to pageIndex and pageSize parameters.
        var result = (from p in people
                        select p).Skip(pageIndex * pageSize).Take(pageSize); 

        return result;
    }

ListView项与真正大列表上的其他项重叠

1 个答案: