当我到达列表末尾时,我正在加载新数据Listview
。当只使用鼠标滚轮时它似乎没问题,但是当使用滚动条时都出错了。主要思想是提供连续性列表的效果。为此,我使用ScrollInToView
以防鼠标滚轮正常工作。但是在滚动条的情况下,它不起作用。有谁知道如何解决它?
Xaml
部分:
<Window x:Class="WpfApplication1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525" Name="SomeContol" >
<Window.Resources>
<DataTemplate x:Key="Item">
<Grid Grid.Column="1" Height="65" HorizontalAlignment="Left" Name="grid1" VerticalAlignment="Top" Width="239">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="64*" />
<ColumnDefinition Width="175*" />
</Grid.ColumnDefinitions>
<TextBlock Height="30" HorizontalAlignment="Center" Margin="6,17,0,18" Name="textBlock1" Text="{Binding Number}" VerticalAlignment="Center" Width="58" TextAlignment="Center" FontSize="20" FontFamily="Shruti" TextTrimming="WordEllipsis" TextWrapping="Wrap" />
<Grid.Background>
<LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
<GradientStop Color="#FF9D76FF" Offset="0.163" />
<GradientStop Color="#08389FFF" Offset="0.878" />
</LinearGradientBrush>
</Grid.Background>
</Grid>
</DataTemplate>
</Window.Resources>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="65*" />
<RowDefinition Height="246*" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="264*" />
<ColumnDefinition Width="239*" />
</Grid.ColumnDefinitions>
<ListBox
SelectedItem="{Binding ElementName=SomeContol, Path=SelectedOne}"
ScrollViewer.ScrollChanged="listBox1_ScrollChanged"
SelectionChanged="listBox1_SelectionChanged"
ItemTemplate="{StaticResource Item}"
ScrollViewer.CanContentScroll="False"
ItemsSource="{Binding ElementName=SomeContol, Path=SomeColection}"
Height="246"
HorizontalAlignment="Left"
Name="listBox1"
VerticalAlignment="Top"
Width="247"
Grid.Row="1" />
</Grid>
代码背后的代码:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Collections.ObjectModel;
using System.Windows.Controls.Primitives;
namespace WpfApplication1
{
/// <summary>
/// Логика взаимодействия для MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
private DateTime DT = DateTime.Now;
public ObservableCollection<Axle> SomeColection
{
get { return (ObservableCollection<Axle>)GetValue(SomeColectionProperty); }
set { SetValue(SomeColectionProperty, value); }
}
public Axle SelectedOne
{
get { return (Axle)GetValue(SelectedOneProperty); }
set { SetValue(SelectedOneProperty, value); }
}
// Using a DependencyProperty as the backing store for SelectedOne. This enables animation, styling, binding, etc...
public static readonly DependencyProperty SelectedOneProperty =
DependencyProperty.Register("SelectedOne", typeof(Axle), typeof(MainWindow), new UIPropertyMetadata(null));
// Using a DependencyProperty as the backing store for SomeColection. This enables animation, styling, binding, etc...
public static readonly DependencyProperty SomeColectionProperty =
DependencyProperty.Register("SomeColection", typeof(ObservableCollection<Axle>), typeof(MainWindow), new UIPropertyMetadata(null));
public int count = 0;
public MainWindow()
{
SomeColection = new ObservableCollection<Axle>();
for(int i = 0; i < 30 ; i++)
{
count++;
SomeColection.Add(new Axle(count, count + i));
}
InitializeComponent();
}
private void listBox1_ScrollChanged(object sender, ScrollChangedEventArgs e)
{
if (((e.ExtentHeight) == (e.VerticalOffset + e.ViewportHeight)))
{
//Go Down
if (DT < DateTime.Now)
{
for (int i = 0; i < 20; i++)
{
count++;
SomeColection.RemoveAt(0);
SomeColection.Add(new Axle(count, count + i));
}
SelectedOne = SomeColection[6];
//SelectedOne = SomeColection[30 - (int)System.Math.Round(e.ViewportHeight / 65)];
DT = DateTime.Now.AddSeconds(1);
}
}
if ((e.VerticalOffset == 0))
{
//Go Up
if (count > 31)
{
if(DT<DateTime.Now)
{
for (int i = 0; i < 20; i++)
{
count--;
SomeColection.RemoveAt(29);
SomeColection.Insert(0, new Axle(count - 29, i));
}
SelectedOne = SomeColection[22];
DT = DateTime.Now.AddSeconds(1);
}
}
}
}
private void listBox1_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
Selector selector = sender as Selector;
if (selector is ListBox)
{
(selector as ListBox).ScrollIntoView(selector.SelectedItem);
}
}
}
}