WPF:如何避免 ListBox 或 ListView 中选中的复选框闪烁? [英] WPF: How can I avoid the flickering of the checked checkboxes in a ListBox or a ListView?

问题描述

如何避免 WPF ListBox 或 ListView 中选中的复选框闪烁?可以通过单击刷新"按钮或滚动列表框，使用下面的代码重现它.如果 IsChecked 为 false，则不会闪烁.

How can I avoid the flickering of the checked checkboxes in a WPF ListBox or ListView ? It can be reproduced with the code below by clicking on the Refresh button or by scrolling the listbox. If IsChecked is false, it does not flicker.

Window1.xaml:

Window1.xaml:

<Window x:Class="WpfApplication6.Window1"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="Window1" Height="300" Width="300">
    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition/>
            <ColumnDefinition/>
        </Grid.ColumnDefinitions>
        <ListBox Name="listBox">
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <StackPanel Orientation="Horizontal">
                        <CheckBox IsChecked="True"
                                  VerticalAlignment="Center"/>
                        <Label Padding="3"
                               Content="{Binding}"/>
                    </StackPanel>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>
        <Button Content="Refresh"
                Grid.Column="1"
                VerticalAlignment="Top"
                Click="Button_Click"/>
    </Grid>
</Window>

Window1.xaml.cs:

Window1.xaml.cs:

using System.Windows;

namespace WpfApplication6
{
    partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
            Button_Click(null, null);
        }

        void Button_Click(object sender, RoutedEventArgs e)
        {
            var items = new int[10000];
            for (int i = 0; i < items.Length; i++)
                items[i] = i + 1;
            listBox.ItemsSource = items;
        }
    }
}

推荐答案

它闪烁是因为您正在丢弃旧的 ItemsSource 并创建一个新的.这需要重做所有绑定，并且需要重新创建显示每个项目的模板.为了避免重新创建整个列表的性能开销，只需修改现有 ItemsSource 中的单个元素.然后绑定到更改的属性和/或项目的 DataTemplate 部分将自动更新，而无需重新创建整个列表视图.这样做将消除您看到的闪烁".

It is flickering because you are throwing out the old ItemsSource and creating a new one. This requires all of the binding to be redone, and the template displaying each item needs to be recreated. To avoid the performance overhead of recreating an entire list, just modify the individual elements in the existing ItemsSource. Then the part of the DataTemplate that is bound to the changed properties and/or items will automatically update without needing to recreate the whole list view. Doing this will eliminate the "flicker" you are seeing.

试试这个代码隐藏:

public partial class MainWindow : Window
{
    private ObservableCollection<object> _items;

    public MainWindow()
    {
        InitializeComponent();

        _items = new ObservableCollection<object>();
        for (int i = 0; i < 10000; i++)
            _items.Add(i + 1);
        listBox.ItemsSource = _items;

    }

    void Button_Click(object sender, RoutedEventArgs e)
    {
        for (int i = 0; i < _items.Count;i++)
        {
            if (!(_items[i] is int)) continue;
            _items[i] = (int)_items[i] + 1;
        }
    }
}

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