列表框未选择所选项目

Question

见下面的代码
视觉工作室 2010
ListBox 上方有一个 TextBox。
通过绑定文本框可以在选择项目时变大或变小。
这会导致 ListBox 移动。
当 ListBox 移动时，选中的项目不是被点击的项目。
选中的项目是移动的 ListBox 上鼠标下的项目。
有时它甚至根本不会选择（尝试从 9 到 10 或从 10 到 9）。
在此代码中重现问题的偶数和奇数产生不同的长度。
因此，如果您从奇数变为奇数，甚至从偶数变为偶数，那么没问题。
如果您从顶部的奇数到底部的偶数（不滚动），则有时会选择一个不在视图中的项目。
在实际代码中，TextBox 是对项目的描述，描述的长度不同。
有趣的是在调试中，在 get { return boundText; 上有一个断点； } 然后它会选择正确的项目。
我认为它会处理选择，然后测量 UI，然后在新 UI 上再次处理选择。
由于它在调试中的行为不同，因此很难弄清楚。

<Window x:Class="ListBoxMissClick.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"
        DataContext="{Binding RelativeSource={RelativeSource Self}}">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="*"/>
        </Grid.ColumnDefinitions>
        <TextBox Grid.Row="0" Grid.Column="0" Text="{Binding Path=BoundText}" TextWrapping="Wrap" />
        <ListBox Grid.Row="1" Grid.Column="0" ItemsSource="{Binding Path=BoundList}" SelectedItem="{Binding Path=BoundListSelected, Mode=TwoWay}"/>
    </Grid>
</Window>

using System.ComponentModel;

namespace ListBoxMissClick
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window, INotifyPropertyChanged
    {
        private string boundListSelected;
        private string boundText = string.Empty;
        private List<string> boundList = new List<string>();
        private bool shortLong = true;
        public event PropertyChangedEventHandler PropertyChanged;

        protected void NotifyPropertyChanged(String info)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(info));
            }
        }

        public MainWindow()
        {
            for (int i = 0; i < 1000; i++)
            {
                boundList.Add(i.ToString());
            }

            InitializeComponent();

        }
        public string BoundText 
        { 
            get { return boundText; }
            set 
            { 
                if (boundText != value)
                {
                    boundText = value;
                    NotifyPropertyChanged("BoundText");
                }
            }
        }
        public List<string> BoundList { get { return boundList; } }
        public string BoundListSelected
        {
            get { return boundListSelected; }
            set
            {
                boundListSelected = value;
                if (Int32.Parse(value) % 2 == 0)
                {
                    BoundText = value.ToString() + " something very long something very long something very long something very long something very long something very long something very long something very long something very long something very longsomething very long something very long something very long something very long something very longsomething very long something very long something very long something very long something very longsomething very long something very long something very long something very long something very longsomething very long something very long something very long something very long something very long";
                }
                else
                {
                    BoundText = value.ToString() + " something short "; 
                }
             }
        }

        private void ListBox_MouseDoubleClick(object sender, MouseButtonEventArgs e)
        {
            BoundText = " something very long something very long something very long something very long something very long something very long something very long something very long something very long something very longsomething very long something very long something very long something very long something very longsomething very long something very long something very long something very long something very longsomething very long something very long something very long something very long something very longsomething very long something very long something very long something very long something very long";
        }
    }
}

除了接受的答案 Mouse.Capture 和 ReleaseMouseCapture 工作。

set
{
    Mouse.Capture(this);
    {
        boundListSelected = value;
        if (Int32.Parse(value) % 2 == 0)
        {
            BoundText = value.ToString() + " something very long something very long something very long something very long something very long something very long something very long something very long something very long something very longsomething very long something very long something very long something very long something very longsomething very long something very long something very long something very long something very longsomething very long something very long something very long something very long something very longsomething very long something very long something very long something very long something very long";
        }
        else
        {
            BoundText = value.ToString() + " something short ";
        }
    }
    ReleaseMouseCapture();
}

Answer 1

我已经稍微改写了您的代码。诀窍是使用 MouseCapture 来避免处理多个事件（使用您的原始代码，由于在按下鼠标按钮时布局发生了变化，因此 listBox 一次单击最多可以选择三个）

代码如下：

MainWindow.xaml

<Window xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        x:Class="TextEditor.MainWindow"
        Title="MainWindow" Height="350" Width="525">

    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>
        <TextBox Grid.Row="0" Text="{Binding Path=BoundText}" TextWrapping="Wrap" />
        <ListBox Grid.Row="1" 
                 ItemsSource="{Binding Path=BoundList}" 
                 SelectedItem="{Binding Path=BoundListSelected, Mode=TwoWay}"/>
    </Grid>

</Window>

MainWindow.xaml.cs

using System;
using System.Collections.Generic;
using System.Windows;
using System.Windows.Input;

namespace TextEditor
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public string BoundText
        {
            get { return (string)GetValue(BoundTextProperty); }
            set { SetValue(BoundTextProperty, value); }
        }

        // Using a DependencyProperty as the backing store for BoundText.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty BoundTextProperty =
            DependencyProperty.Register("BoundText", typeof(string), typeof(MainWindow), new PropertyMetadata(string.Empty));

        public string BoundListSelected
        {
            get { return (string)GetValue(BoundListSelectedProperty); }
            set { SetValue(BoundListSelectedProperty, value); }
        }

        // Using a DependencyProperty as the backing store for BoundListSelected.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty BoundListSelectedProperty =
            DependencyProperty.Register("BoundListSelected", typeof(string), typeof(MainWindow), new PropertyMetadata(string.Empty, OnBoundListSelectedChanged));

        private static void OnBoundListSelectedChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            var mainWindow = d as MainWindow;
            var value = e.NewValue as string;

            Mouse.Capture(mainWindow);

            if (Int32.Parse(value) % 2 == 0)
            {
                mainWindow.BoundText = value.ToString() + " something very long something very long something very long something very long something very long something very long something very long something very long something very long something very longsomething very long something very long something very long something very long something very longsomething very long something very long something very long something very long something very longsomething very long something very long something very long something very long something very longsomething very long something very long something very long something very long something very long";
            }
            else
            {
                mainWindow.BoundText = value.ToString() + " something short ";
            }

            mainWindow.ReleaseMouseCapture();
        }

        public MainWindow()
        {
            for (int i = 0; i < 1000; i++)
            {
                boundList.Add(i.ToString());
            }

            InitializeComponent();
            DataContext = this;
        }

        public List<string> BoundList { get { return boundList; } }
        private List<string> boundList = new List<string>();
    }
}

编辑：我实际上改变了 MainWindow 的编码方式（没有必要在 DependencyObject 上实现 INotifyPropertyChanged，所以我只是删除了它并设置了两个依赖属性），但您可以尝试解决您的问题您的原始代码只需在设置 BoundText 之前捕获鼠标，然后释放它。

Answer 2

您可以在BoundListSelected setter 中添加Thread.Sleep 来解决您的问题，但我认为在这种情况下更好的解决方案是使用网格列。当你使用列时，你不需要使用Thread.Sleep。

public string BoundListSelected
{
    get { return boundListSelected; }
    set
    {
        Thread.Sleep(TimeSpan.FromSeconds(.2));
        boundListSelected = value;
        if (Int32.Parse(value) % 2 == 0)
        {
            BoundText = value.ToString() + " something very long something very long something very long something very long something very long something very long something very long something very long something very long something very longsomething very long something very long something very long something very long something very longsomething very long something very long something very long something very long something very longsomething very long something very long something very long something very long something very longsomething very long something very long something very long something very long something very long";
        }
        else
        {
            BoundText = value.ToString() + " something short ";
        }
    }
}

如果你不想使用Thread.Sleep，你可以使用带有列的网格：

<Grid>
    <Grid.ColumnDefinitions>            
        <ColumnDefinition Width="*"/>
        <ColumnDefinition Width="*"/>
    </Grid.ColumnDefinitions>
    <TextBox Grid.Column="0" Text="{Binding Path=BoundText}" TextWrapping="Wrap" />
    <ListBox Grid.Column="1" ItemsSource="{Binding Path=BoundList}" SelectedItem="{Binding Path=BoundListSelected, Mode=TwoWay}"/>
</Grid>