Question

每当我实施分组时，我遇到ListView的主要性能问题。我在StackOverflow上找到somewhat similar questions，但似乎都没有帮助！

这是我目前的情况（我简化了我的项目，因此噪音更少）：

我有一个ContentControl，其中ListView为孩子。 ListView绑定到ObservableCollection，最初为空。随着时间的推移，对象被添加到集合中（在此示例中，使用DispatcherTimer每10秒添加500个项目）。 ObservableCollection的大小会有所不同，但收藏可能会超过25,000个项目。

当ObservableCollection小于2000（不完全确切的数字）时，列大小调整如下：

enter image description here

但是，随着更多对象添加到ObservableCollection，性能会明显下降（ 您需要向下滚动才能实现此目标 ）。

Notice how slow it is?

这最终会导致Application锁定。

我认为可以使用Virtualization解决问题，所以我尝试使用以下内容：

<ListView x:Name="ListView1"
                  Style="{DynamicResource lvStyle}"
                  VirtualizingPanel.IsVirtualizingWhenGrouping="True"
                  VirtualizingPanel.IsVirtualizing="True"
                  VirtualizingPanel.IsContainerVirtualizable="True"
                  ScrollViewer.IsDeferredScrollingEnabled="True">

然而，似乎没有任何作用！

更不用说，VirtualizingPanel.IsVirtualizingWhenGrouping="True"导致ListView完全锁定。

我也调查了Paul McClean's excellent Data Virtualization，但它没有处理分组。

问题： 在ListView中对项目进行分组时，是否有办法调整列的大小而不会显着影响应用程序的性能？

理想情况下，我希望减少内存开销，所以我都在实现某种异步解决方案。

CODE：

XAML：

<ContentControl x:Class="ListViewDemo.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
        xmlns:local="clr-namespace:ListViewDemo"
        xmlns:sys="clr-namespace:System;assembly=mscorlib"
        xmlns:dat="clr-namespace:System.Windows.Data;assembly=PresentationFramework"
        xmlns:Themes="clr-namespace:Microsoft.Windows.Themes;assembly=PresentationFramework.Classic" 
        mc:Ignorable="d" 
        d:DesignHeight="400" d:DesignWidth="300">
    <ContentControl.Resources>
    <Style x:Key="lvStyle" TargetType="{x:Type ListView}">
        <Setter Property="VirtualizingStackPanel.IsVirtualizing" Value="True"/>
        <Setter Property="VirtualizingStackPanel.VirtualizationMode" Value="Recycling"/>
        <Setter Property="ScrollViewer.IsDeferredScrollingEnabled" Value="True"/>
        <Setter Property="ListView.ItemsSource" Value="{Binding}"/>
        <Setter Property="ListView.View">
            <Setter.Value>
                <GridView>
                    <GridViewColumn Header="Name">
                        <GridViewColumn.CellTemplate>
                            <DataTemplate>
                                <TextBlock Text="{Binding Name}"/>
                            </DataTemplate>
                        </GridViewColumn.CellTemplate>
                    </GridViewColumn>
                    <GridViewColumn Header="Date">
                        <GridViewColumn.CellTemplate>
                            <DataTemplate>
                                <TextBlock Text="{Binding Date}"/>
                            </DataTemplate>
                        </GridViewColumn.CellTemplate>
                    </GridViewColumn>
                    <GridViewColumn Header="Desc">
                        <GridViewColumn.CellTemplate>
                            <DataTemplate>
                                <TextBlock Text="{Binding Desc}"/>
                            </DataTemplate>
                        </GridViewColumn.CellTemplate>
                    </GridViewColumn>
                </GridView>
            </Setter.Value>
        </Setter>
        </Style>
    </ContentControl.Resources>

    <Grid>
        <ListView x:Name="ListView1"
                      Style="{DynamicResource lvStyle}"
                      VirtualizingPanel.IsVirtualizingWhenGrouping="True"
                      VirtualizingPanel.IsVirtualizing="True"
                      VirtualizingPanel.IsContainerVirtualizable="True"
                      ScrollViewer.IsDeferredScrollingEnabled="True">
            <ListView.GroupStyle>
                <GroupStyle>
                    <GroupStyle.ContainerStyle>
                        <Style TargetType="{x:Type GroupItem}">
                            <Setter Property="Template">
                                <Setter.Value>
                                    <ControlTemplate TargetType="{x:Type GroupItem}">
                                        <DockPanel>
                                            <Border DockPanel.Dock="Top">
                                                <TextBlock x:Name="groupItem"
                                                            Text="{Binding ItemCount, StringFormat={}({0} Results)}"></TextBlock>
                                            </Border>
                                            <ItemsPresenter DockPanel.Dock="Bottom"></ItemsPresenter>
                                        </DockPanel>
                                    </ControlTemplate>
                                </Setter.Value>
                            </Setter>
                        </Style>
                    </GroupStyle.ContainerStyle>
                </GroupStyle>
            </ListView.GroupStyle>
        </ListView>
    </Grid>
</ContentControl>

代码隐藏：

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
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.Windows.Threading;

namespace ListViewDemo
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : ContentControl
    {
        private ObservableCollection<Event> eventCollection = new ObservableCollection<Event>();

        public MainWindow()
        {
            InitializeComponent();

            DispatcherTimer dispatcherTimer = new DispatcherTimer();
            dispatcherTimer.Tick += new EventHandler(dispatcherTimer_Tick);
            dispatcherTimer.Interval = new TimeSpan(0, 0, 10);
            dispatcherTimer.Start();

            ListView1.ItemsSource = eventCollection;
            ListView1.Items.SortDescriptions.Add(new SortDescription("Name", ListSortDirection.Descending));
            ListView1.Items.SortDescriptions.Add(new SortDescription("Date", ListSortDirection.Descending));
            ListView1.Items.GroupDescriptions.Add(new PropertyGroupDescription("Seconds"));
        }

        private void dispatcherTimer_Tick(object sender, EventArgs e)
        {
            for(var i = 0; i < 500; i++){
                eventCollection.Add(new Event
                {
                    Name = string.Format("Name_{0}", eventCollection.Count),
                    Date = DateTime.Now.ToString("MM.dd.yy HH:mm"),
                    Seconds = Convert.ToInt32(DateTime.Now.ToString("ss")),
                    Desc = "Description"
                });
            }
        }

        public class Event
        {
            public string Name { get; set; }
            public string Date { get; set; }
            public int Seconds { get; set; }
            public string Desc { get; set; }
        }

    }

}

Answer 1

您的性能问题是由于未使用IsVirtualizingWhenGrouping

您提到使用IsVirtualizingWhenGrouping锁定了您的应用程序，这是一个已知的WPF问题（有关使用自定义GroupStyle和IsVirtualizingWhenGrouping时发生此错误的详细信息，请参阅：http://connect.microsoft.com/VisualStudio/feedback/details/780146/freeze-when-using-virtualizingpanel-isvirtualizingwhengrouping设为真）

以下是解决问题的快速工作方法：您只需在GroupStyle ControlTemplate中添加扩展器即可。然后，您可以使用IsVirtualizingWhenGrouping，然后在滚动/调整列大小时获得良好的性能。

以下是适用于我的机器的代码:(我将所有内容直接放在MainWindow中以简化一点）

<Window x:Class="WpfApplication21.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">
    <Window.Resources>

        <Style x:Key="lvStyle" TargetType="{x:Type ListView}" >

            <Setter Property="ListView.ItemsSource" Value="{Binding}"/>
            <Setter Property="ListView.View">
                <Setter.Value>
                    <GridView>
                        <GridViewColumn Header="Name">
                            <GridViewColumn.CellTemplate>
                                <DataTemplate>
                                    <TextBlock Text="{Binding Name}"/>
                                </DataTemplate>
                            </GridViewColumn.CellTemplate>
                        </GridViewColumn>
                        <GridViewColumn Header="Date">
                            <GridViewColumn.CellTemplate>
                                <DataTemplate>
                                    <TextBlock Text="{Binding Date}"/>
                                </DataTemplate>
                            </GridViewColumn.CellTemplate>
                        </GridViewColumn>
                        <GridViewColumn Header="Desc">
                            <GridViewColumn.CellTemplate>
                                <DataTemplate>
                                    <TextBlock Text="{Binding Desc}"/>
                                </DataTemplate>
                            </GridViewColumn.CellTemplate>
                        </GridViewColumn>
                    </GridView>
                </Setter.Value>
            </Setter>
        </Style>
    </Window.Resources>

    <Grid>
        <ListView x:Name="ListView1"
                  Style="{DynamicResource lvStyle}"
                  VirtualizingPanel.IsVirtualizing="True"
                  VirtualizingPanel.IsVirtualizingWhenGrouping="True">
            <ListView.GroupStyle>
                <GroupStyle>
                    <GroupStyle.ContainerStyle>
                        <Style TargetType="{x:Type GroupItem}">
                            <Setter Property="Template">
                                <Setter.Value>
                                    <ControlTemplate TargetType="{x:Type GroupItem}">
                                        <Expander IsExpanded="True">
                                            <DockPanel>
                                                <Border DockPanel.Dock="Top">
                                                    <TextBlock x:Name="groupItem"
                                                                Text="{Binding ItemCount, StringFormat={}({0} Results)}"></TextBlock>
                                                </Border>
                                                <ItemsPresenter x:Name="groupItemPresenter" DockPanel.Dock="Bottom"></ItemsPresenter>
                                            </DockPanel>
                                        </Expander>
                                    </ControlTemplate>
                                </Setter.Value>
                            </Setter>
                        </Style>
                    </GroupStyle.ContainerStyle>
                </GroupStyle>
            </ListView.GroupStyle>
        </ListView>
    </Grid>
</Window>

编辑：这是一个“隐藏”扩展器的ControlTemplate。这是我删除不必要部分的原始内容：

<ControlTemplate x:Key="CustomExpanderControlTemplate" TargetType="{x:Type Expander}">
        <Border BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" CornerRadius="3" SnapsToDevicePixels="True">
            <DockPanel>
                <ToggleButton x:Name="HeaderSite" ContentTemplate="{TemplateBinding HeaderTemplate}" Content="{TemplateBinding Header}" DockPanel.Dock="Top" Foreground="{TemplateBinding Foreground}" FontWeight="{TemplateBinding FontWeight}" FontStyle="{TemplateBinding FontStyle}" FontStretch="{TemplateBinding FontStretch}" FontSize="{TemplateBinding FontSize}" FontFamily="{TemplateBinding FontFamily}" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" IsChecked="{Binding IsExpanded, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" MinWidth="0" MinHeight="0" Padding="{TemplateBinding Padding}" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}">
                    <ToggleButton.FocusVisualStyle>
                        <Style>
                            <Setter Property="Control.Template">
                                <Setter.Value>
                                    <ControlTemplate>
                                        <Border>
                                            <Rectangle Margin="0" SnapsToDevicePixels="True" Stroke="Black" StrokeThickness="1" StrokeDashArray="1 2"/>
                                        </Border>
                                    </ControlTemplate>
                                </Setter.Value>
                            </Setter>
                        </Style>
                    </ToggleButton.FocusVisualStyle>
                    <ToggleButton.Style>
                        <Style TargetType="{x:Type ToggleButton}">
                            <Setter Property="Template">
                                <Setter.Value>
                                    <ControlTemplate TargetType="{x:Type ToggleButton}">
                                        <Border Padding="{TemplateBinding Padding}">
                                            <Grid Background="Transparent" SnapsToDevicePixels="False">
                                                <Grid.ColumnDefinitions>
                                                    <ColumnDefinition Width="*"/>
                                                </Grid.ColumnDefinitions>
                                                <ContentPresenter ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" Grid.Column="0" ContentStringFormat="{TemplateBinding ContentStringFormat}" HorizontalAlignment="Left" Margin="4,0,0,0" RecognizesAccessKey="True" SnapsToDevicePixels="True" VerticalAlignment="Center"/>
                                            </Grid>
                                        </Border>
                                    </ControlTemplate>
                                </Setter.Value>
                            </Setter>
                        </Style>
                    </ToggleButton.Style>
                </ToggleButton>
                <ContentPresenter x:Name="ExpandSite" ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" ContentStringFormat="{TemplateBinding ContentStringFormat}" DockPanel.Dock="Bottom" Focusable="False" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}" Visibility="Collapsed" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
            </DockPanel>
        </Border>
        <ControlTemplate.Triggers>
            <Trigger Property="IsExpanded" Value="True">
                <Setter Property="Visibility" TargetName="ExpandSite" Value="Visible"/>
            </Trigger>
            <Trigger Property="ExpandDirection" Value="Right">
                <Setter Property="DockPanel.Dock" TargetName="ExpandSite" Value="Right"/>
                <Setter Property="DockPanel.Dock" TargetName="HeaderSite" Value="Left"/>
                <Setter Property="Style" TargetName="HeaderSite">
                    <Setter.Value>
                        <Style TargetType="{x:Type ToggleButton}">
                            <Setter Property="Template">
                                <Setter.Value>
                                    <ControlTemplate TargetType="{x:Type ToggleButton}">
                                        <Border Padding="{TemplateBinding Padding}">
                                            <Grid Background="Transparent" SnapsToDevicePixels="False">
                                                <Grid.RowDefinitions>
                                                    <RowDefinition Height="19"/>
                                                    <RowDefinition Height="*"/>
                                                </Grid.RowDefinitions>
                                                <Grid>
                                                    <Grid.LayoutTransform>
                                                        <TransformGroup>
                                                            <RotateTransform Angle="-90"/>
                                                        </TransformGroup>
                                                    </Grid.LayoutTransform>
                                                    <Ellipse x:Name="circle" Fill="Transparent" HorizontalAlignment="Center" Height="19" Stroke="DarkGray" VerticalAlignment="Center" Width="19"/>
                                                    <Path x:Name="arrow" Data="M1,1.5L4.5,5 8,1.5" HorizontalAlignment="Center" SnapsToDevicePixels="False" Stroke="#FF666666" StrokeThickness="2" VerticalAlignment="Center"/>
                                                </Grid>
                                                <ContentPresenter ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" ContentStringFormat="{TemplateBinding ContentStringFormat}" HorizontalAlignment="Center" Margin="0,4,0,0" Grid.Row="1" RecognizesAccessKey="True" SnapsToDevicePixels="True" VerticalAlignment="Top"/>
                                            </Grid>
                                        </Border>
                                        <ControlTemplate.Triggers>
                                            <Trigger Property="IsChecked" Value="True">
                                                <Setter Property="Data" TargetName="arrow" Value="M1,4.5L4.5,1 8,4.5"/>
                                            </Trigger>
                                            <Trigger Property="IsMouseOver" Value="True">
                                                <Setter Property="Stroke" TargetName="circle" Value="#FF3C7FB1"/>
                                                <Setter Property="Fill" TargetName="circle" Value="Transparent"/>
                                                <Setter Property="Stroke" TargetName="arrow" Value="#FF222222"/>
                                            </Trigger>
                                            <Trigger Property="IsPressed" Value="True">
                                                <Setter Property="Stroke" TargetName="circle" Value="#FF526C7B"/>
                                                <Setter Property="StrokeThickness" TargetName="circle" Value="1.5"/>
                                                <Setter Property="Fill" TargetName="circle" Value="Transparent"/>
                                                <Setter Property="Stroke" TargetName="arrow" Value="#FF003366"/>
                                            </Trigger>
                                            <Trigger Property="IsEnabled" Value="False">
                                                <Setter Property="Stroke" TargetName="circle" Value="DarkGray"/>
                                                <Setter Property="Fill" TargetName="circle" Value="Transparent"/>
                                                <Setter Property="Stroke" TargetName="arrow" Value="#FF666666"/>
                                            </Trigger>
                                        </ControlTemplate.Triggers>
                                    </ControlTemplate>
                                </Setter.Value>
                            </Setter>
                        </Style>
                    </Setter.Value>
                </Setter>
            </Trigger>
            <Trigger Property="ExpandDirection" Value="Up">
                <Setter Property="DockPanel.Dock" TargetName="ExpandSite" Value="Top"/>
                <Setter Property="DockPanel.Dock" TargetName="HeaderSite" Value="Bottom"/>
                <Setter Property="Style" TargetName="HeaderSite">
                    <Setter.Value>
                        <Style TargetType="{x:Type ToggleButton}">
                            <Setter Property="Template">
                                <Setter.Value>
                                    <ControlTemplate TargetType="{x:Type ToggleButton}">
                                        <Border Padding="{TemplateBinding Padding}">
                                            <Grid Background="Transparent" SnapsToDevicePixels="False">
                                                <Grid.ColumnDefinitions>
                                                    <ColumnDefinition Width="19"/>
                                                    <ColumnDefinition Width="*"/>
                                                </Grid.ColumnDefinitions>
                                                <Grid>
                                                    <Grid.LayoutTransform>
                                                        <TransformGroup>
                                                            <RotateTransform Angle="180"/>
                                                        </TransformGroup>
                                                    </Grid.LayoutTransform>
                                                    <Ellipse x:Name="circle" Fill="Transparent" HorizontalAlignment="Center" Height="19" Stroke="DarkGray" VerticalAlignment="Center" Width="19"/>
                                                    <Path x:Name="arrow" Data="M1,1.5L4.5,5 8,1.5" HorizontalAlignment="Center" SnapsToDevicePixels="False" Stroke="#FF666666" StrokeThickness="2" VerticalAlignment="Center"/>
                                                </Grid>
                                                <ContentPresenter ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" Grid.Column="1" ContentStringFormat="{TemplateBinding ContentStringFormat}" HorizontalAlignment="Left" Margin="4,0,0,0" RecognizesAccessKey="True" SnapsToDevicePixels="True" VerticalAlignment="Center"/>
                                            </Grid>
                                        </Border>
                                        <ControlTemplate.Triggers>
                                            <Trigger Property="IsChecked" Value="True">
                                                <Setter Property="Data" TargetName="arrow" Value="M1,4.5L4.5,1 8,4.5"/>
                                            </Trigger>
                                            <Trigger Property="IsMouseOver" Value="True">
                                                <Setter Property="Stroke" TargetName="circle" Value="#FF3C7FB1"/>
                                                <Setter Property="Fill" TargetName="circle" Value="Transparent"/>
                                                <Setter Property="Stroke" TargetName="arrow" Value="#FF222222"/>
                                            </Trigger>
                                            <Trigger Property="IsPressed" Value="True">
                                                <Setter Property="Stroke" TargetName="circle" Value="#FF526C7B"/>
                                                <Setter Property="StrokeThickness" TargetName="circle" Value="1.5"/>
                                                <Setter Property="Fill" TargetName="circle" Value="Transparent"/>
                                                <Setter Property="Stroke" TargetName="arrow" Value="#FF003366"/>
                                            </Trigger>
                                            <Trigger Property="IsEnabled" Value="False">
                                                <Setter Property="Stroke" TargetName="circle" Value="DarkGray"/>
                                                <Setter Property="Fill" TargetName="circle" Value="Transparent"/>
                                                <Setter Property="Stroke" TargetName="arrow" Value="#FF666666"/>
                                            </Trigger>
                                        </ControlTemplate.Triggers>
                                    </ControlTemplate>
                                </Setter.Value>
                            </Setter>
                        </Style>
                    </Setter.Value>
                </Setter>
            </Trigger>
            <Trigger Property="ExpandDirection" Value="Left">
                <Setter Property="DockPanel.Dock" TargetName="ExpandSite" Value="Left"/>
                <Setter Property="DockPanel.Dock" TargetName="HeaderSite" Value="Right"/>
                <Setter Property="Style" TargetName="HeaderSite">
                    <Setter.Value>
                        <Style TargetType="{x:Type ToggleButton}">
                            <Setter Property="Template">
                                <Setter.Value>
                                    <ControlTemplate TargetType="{x:Type ToggleButton}">
                                        <Border Padding="{TemplateBinding Padding}">
                                            <Grid Background="Transparent" SnapsToDevicePixels="False">
                                                <Grid.RowDefinitions>
                                                    <RowDefinition Height="19"/>
                                                    <RowDefinition Height="*"/>
                                                </Grid.RowDefinitions>
                                                <Grid>
                                                    <Grid.LayoutTransform>
                                                        <TransformGroup>
                                                            <RotateTransform Angle="90"/>
                                                        </TransformGroup>
                                                    </Grid.LayoutTransform>
                                                    <Ellipse x:Name="circle" Fill="Transparent" HorizontalAlignment="Center" Height="19" Stroke="DarkGray" VerticalAlignment="Center" Width="19"/>
                                                    <Path x:Name="arrow" Data="M1,1.5L4.5,5 8,1.5" HorizontalAlignment="Center" SnapsToDevicePixels="False" Stroke="#FF666666" StrokeThickness="2" VerticalAlignment="Center"/>
                                                </Grid>
                                                <ContentPresenter ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" ContentStringFormat="{TemplateBinding ContentStringFormat}" HorizontalAlignment="Center" Margin="0,4,0,0" Grid.Row="1" RecognizesAccessKey="True" SnapsToDevicePixels="True" VerticalAlignment="Top"/>
                                            </Grid>
                                        </Border>
                                        <ControlTemplate.Triggers>
                                            <Trigger Property="IsChecked" Value="True">
                                                <Setter Property="Data" TargetName="arrow" Value="M1,4.5L4.5,1 8,4.5"/>
                                            </Trigger>
                                            <Trigger Property="IsMouseOver" Value="True">
                                                <Setter Property="Stroke" TargetName="circle" Value="#FF3C7FB1"/>
                                                <Setter Property="Fill" TargetName="circle" Value="Transparent"/>
                                                <Setter Property="Stroke" TargetName="arrow" Value="#FF222222"/>
                                            </Trigger>
                                            <Trigger Property="IsPressed" Value="True">
                                                <Setter Property="Stroke" TargetName="circle" Value="#FF526C7B"/>
                                                <Setter Property="StrokeThickness" TargetName="circle" Value="1.5"/>
                                                <Setter Property="Fill" TargetName="circle" Value="Transparent"/>
                                                <Setter Property="Stroke" TargetName="arrow" Value="#FF003366"/>
                                            </Trigger>
                                            <Trigger Property="IsEnabled" Value="False">
                                                <Setter Property="Stroke" TargetName="circle" Value="DarkGray"/>
                                                <Setter Property="Fill" TargetName="circle" Value="Transparent"/>
                                                <Setter Property="Stroke" TargetName="arrow" Value="#FF666666"/>
                                            </Trigger>
                                        </ControlTemplate.Triggers>
                                    </ControlTemplate>
                                </Setter.Value>
                            </Setter>
                        </Style>
                    </Setter.Value>
                </Setter>
            </Trigger>
            <Trigger Property="IsEnabled" Value="False">
                <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}"/>
            </Trigger>
        </ControlTemplate.Triggers>
    </ControlTemplate>

您可以通过在组样式中设置它来使用它：

<Expander IsExpanded="True" Template="{DynamicResource CustomExpanderControlTemplate}">

Answer 2

我认为问题是绑定到ListView的ObservableCollection以及每个Add（）添加500个项目的情况。每个Add都会引发3个事件。 2 NotifyPropertyChanged - 属性Count和属性Item[]的事件以及集合NotifyCollectionChanged-Event的事件，最多可计入1500个事件。

我已经用我自己的ObservableCollection派生实现交换了ObservableCollection，这个实现允许我添加一系列项目并且只引发一次3个事件。

    public class SmartCollection<T> : ObservableCollection<T> {
        public SmartCollection()
            : base() {

        }

        public SmartCollection(IEnumerable<T> collection)
            : base(collection) {

        }

        public SmartCollection(List<T> list)
            : base(list) {

        }

        public void AddRange(IEnumerable<T> range) {
            foreach (var item in range) {
                Items.Add(item);
            }

            this.OnPropertyChanged(new PropertyChangedEventArgs("Count"));
            this.OnPropertyChanged(new PropertyChangedEventArgs("Item[]"));
            this.OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
        }

        public void Reset(IEnumerable<T> range) {
            if (range == null) {
                throw new ArgumentNullException("range", "range is null");
            }

            var rangeToAdd = range.ToList();
            this.Items.Clear();

            AddRange(rangeToAdd);
        }
    }

使用我的Collection我改变了你的方法，将元素添加到集合

private SmartCollection<Event> eventCollection = new SmartCollection<Event>();

private void dispatcherTimer_Tick(object sender, EventArgs e) {
  List<Event> newEvents = new List<Event>(500);

  for(var i = 0; i < 500; i++){
    newEvents.Add(new Event {
      Name = string.Format("Name_{0}", eventCollection.Count + i),
      Date = DateTime.Now.ToString("MM.dd.yy HH:mm"),
      Seconds = Convert.ToInt32(DateTime.Now.ToString("ss")),
      Desc = "Description"
    });
  }

  eventCollection.AddRange(newEvents);
}

Answer 3

我不确定这个答案是否合适，但是在确定之后我确实得到了这个表现 VirtualizingPanel.ScrollUnit属性为“Item”。问题是，我有一些视觉故障，其中包括在逐行滚动（鼠标滚轮或键向上/向下）时看到分组对象覆盖顶行，并在滚动后立即在行之间模糊渲染器开始清理文本。

VirtualizingPanel.ScrollUnit="Item"

编辑：同时将VirtualizationMode更改回Standard，VirtualizingPanel.VirtualizationMode =“Standard”，并且视觉故障几乎消失。（已经测试了50,000行）。

ListView调整列的性能问题（分组）

CODE：

3 个答案: