wpf - 我如何(完全)在 ListBox 中实现就地编辑？

Question

我正在构建一个应用程序，其中 ListBox 显示其项目的 Description 属性。我想实现与您在 Windows 资源管理器中编辑文件名时发现的相同类型的就地编辑功能，我发现它需要大量工作。

到目前为止，我所拥有的是启动编辑的 ContextMenu。它绑定(bind)到 View 模型中设置 IsEditingDescription 属性的命令。项目模板的样式使其在 IsEditingDescription 为 false 时在 TextBlock 和 TextBox 中显示 Description > 当 IsEditingDescription 为真时。 Description 上的 setter 在设置描述后将 IsEditingDescription 设置为 false。

这非常有效。但是有些它应该做但没有做的事情:

• 用户应该能够通过按 F2 启动编辑。
• 用户应该能够通过按 ESC 键取消编辑。
• 用户应该能够通过按 ENTER 键确认编辑。
• 当用户第二次点击当前选定的项目时，应该启动编辑。
• 出现文本框时应选择描述的文本

我想我可以使用命令和键绑定(bind)来处理前三项，尽管我还不太了解如何进行键绑定(bind)。但我真的想不出一种 MVVMish 的方式来做其他两个。有吗？

Answer 1

这是我不得不反复做的事情，所以我决定扩展 ListView 控件并添加 ItemKeyDown、ItemKeyUp 和 ItemDoubleClick 事件，当 ListView 中的项目处于焦点时，这些事件将被触发。 ListView 派生自 ListBox，因此您应该能够非常轻松地移植它。

/Fx/ListView.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using System.Windows;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Controls;

namespace Fx
{
    public static class Func
    {
        /// <summary>
        /// Finds a specific type of parent up the visual tree.
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="dep"></param>
        /// <returns></returns>
        public static T FindParent<T>(this object obj)
        {
            DependencyObject dep = obj as DependencyObject;
            while ((dep != null) && !(dep is T))
            {
                dep = VisualTreeHelper.GetParent(dep);
            }
            return (dep != null) ? (T)Convert.ChangeType(dep, typeof(T)) : default(T);
        }
    }

    public class ListView:System.Windows.Controls.ListView
    {

        #region public event KeyboardEventHandler ItemKeyDown;
        /// <summary>
        /// Occurs when a key is pressed when a ListViewItem in this
        /// ListView is in focus.
        /// </summary>
        public event KeyEventHandler ItemKeyDown;

        /// <summary>
        /// Raises the ItemKeyDown event for a ListViewitem in this ListView.
        /// </summary>
        /// <param name="item"></param>
        /// <param name="e"></param>
        public void OnItemKeyDown(ListViewItem item, KeyEventArgs e)
        {
            if (ItemKeyDown != null)
                ItemKeyDown(item, e);
        }

        /// <summary>
        /// Handle they KeyDown event on the ListView, find the related
        /// ListViewItem and raise the ItemKeyDown event respectively.
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void ListView_KeyDown(object sender, KeyEventArgs e)
        {
            ListViewItem item = Func.FindParent<ListViewItem>(e.OriginalSource);
            if (item != null)
                OnItemKeyDown(item, e);
        }
        #endregion

        #region public event KeyboardEventHandler ItemKeyUp;
        /// <summary>
        /// Occurs when a key is released when a ListViewItem in this
        /// ListView is in focus.
        /// </summary>
        public event KeyEventHandler ItemKeyUp;

        /// <summary>
        /// Raises the ItemKeyUp event for a ListViewitem in this ListView.
        /// </summary>
        /// <param name="item"></param>
        /// <param name="e"></param>
        public void OnItemKeyUp(ListViewItem item, KeyEventArgs e)
        {
            if (ItemKeyUp != null)
                ItemKeyUp(item, e);
        }

        /// <summary>
        /// Handle they KeyUp event on the ListView, find the related
        /// ListViewItem and raise the ItemKeyUp event respectively.
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void ListView_KeyUp(object sender, KeyEventArgs e)
        {
            ListViewItem item = Func.FindParent<ListViewItem>(e.OriginalSource);
            if (item != null)
                OnItemKeyUp(item, e);
        }
        #endregion

        #region public event MouseButtonEventHandler ItemDoubleClick;
        /// <summary>
        /// Occurs when a ListViewItem in this Listview is double clicked.
        /// </summary>
        public event MouseButtonEventHandler ItemDoubleClick;

        /// <summary>
        /// Raise the ItemDoubleClick event for a ListViewItem.
        /// </summary>
        /// <param name="item"></param>
        /// <param name="e"></param>
        public void OnItemDoubleClick(ListViewItem item, MouseButtonEventArgs e)
        {
            if (ItemDoubleClick != null)
                ItemDoubleClick(item, e);
        }

        /// <summary>
        /// Handle the MouseDoubleClick event for the ListView, find the related
        /// ListViewItem and raise the ItemDoubleClick event respectively.
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void ListView_MouseDoubleClick(object sender, MouseButtonEventArgs e)
        {
            ListViewItem item = Func.FindParent<ListViewItem>(e.OriginalSource);
            if (item != null)
                OnItemDoubleClick(item, e);
        }
        #endregion

        public ListView()
        {
            MouseDoubleClick += new MouseButtonEventHandler(ListView_MouseDoubleClick);
            KeyDown += new KeyEventHandler(ListView_KeyDown);
            KeyUp += new KeyEventHandler(ListView_KeyUp);
        }
    }
}

现在使用它.../Pages/EmployeesPage.xaml

<UserControl x:Class="TestApp.Pages.EmployeesPage"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:fx="clr-namespace:Fx"
             Width="800" Height="450">
    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="300" />
            <ColumnDefinition />
        </Grid.ColumnDefinitions>
        <StackPanel Grid.Column="0">
            <TextBlock Text="List Items" FontWeight="Bold" FontSize="18" />

            <!-- here is the main part -->
            <fx:ListView x:Name="EmployeesList" ItemDoubleClick="EmployeesList_ItemDoubleClick" ItemKeyDown="EmployeesList_ItemKeyDown" />
            <!-- main part ends here -->

        </StackPanel>
    </Grid>
</UserControl>

/Pages/EmployeesPage.xaml.cs

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;

namespace TestApp.Pages
{
    /// <summary>
    /// Interaction logic for EmployeesPage.xaml
    /// </summary>
    public partial class EmployeesPage : UserControl
    {
        public EmployeesPage()
        {
            InitializeComponent();

            // Fill the ListView with data...
            // EmployeesList.ItemsSource = SomeObservableCollectionOrDataSource
        }

        private void EmployeesList_ItemDoubleClick(object sender, MouseButtonEventArgs e)
        {
            MessageBox.Show("an item was double clicked");

            ListViewItem item = sender as ListViewItem;
            // entityType obj = item.DataContext as entityType

            // you can begin editing here
        }

        private void EmployeesList_ItemKeyDown(object sender, KeyEventArgs e)
        {
            MessageBox.Show(e.Key.ToString() + " key was pressed on an item");

            ListViewItem item = sender as ListViewItem;
            // entityType obj = item.DataContext as entityType

            if (e.Key == Key.F2)
            {
                // begin editing here
            }
            else if (e.Key == Key.Enter)
            {
                // end editing here
            }
            else if (e.Key == Key.Escape)
            {
                // cancel editing here
            }
        }
    }
}

希望这至少对您有用。祝您好运。