Question

XAML：

<Window x:Class="WpfApp_ListBoxTest.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>
  <ListBox Name="lb" Margin="0,0,0,70"></ListBox>
  <Button Height="23" HorizontalAlignment="Left" Margin="12,0,0,41" Name="btnAdd" VerticalAlignment="Bottom" Content="Add item" Width="75" Click="btnAdd_Click"></Button>
  <TextBox Height="23" Margin="93,0,12,41" Name="txtInput" VerticalAlignment="Bottom" />
  <Button Height="23" HorizontalAlignment="Left" Margin="12,0,0,12" Name="btnGet" VerticalAlignment="Bottom" Content="Get value" Width="75" Click="btnGet_Click"></Button>
  <TextBox Height="23" Margin="93,0,12,12" Name="txtReturn" VerticalAlignment="Bottom" IsReadOnly="True" />
 </Grid>
</Window>

Csharp的：

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.Xml;

namespace WpfApp_ListBoxTest
{
 /// <summary>
 /// Interaction logic for Window1.xaml
 /// </summary>
 public partial class Window1 : Window
 {
  public Window1()
  {
   InitializeComponent();
  }

  private void btnAdd_Click(object sender, RoutedEventArgs e)
  {
   TextBox txt = new TextBox();
   txt.Width = 200;
   txt.Text = txtInput.Text;
   lb.Items.Add(txt);
  }

  private void btnGet_Click(object sender, RoutedEventArgs e)
  {
   // What do I need to write here to get the value of the Text property of the selected TextBox?

  }
 }
}

截图:(抱歉，我不允许直接发布图片） http://i825.photobucket.com/albums/zz180/mGlushed/get_listbox_item_property.png

（在上图中，我想点击“获取值”按钮时得到值“b”。）

我想知道是否有一种简单的方法可以实现这一点。

我是WPF的新手，所以我只知道这么做很长一段路，即：创建一个数组。每次创建新的TextBox时，将其添加到数组中。然后通过数组访问TextBox'es。但我认为这听起来不是很理想。

Answer 1

做你想做的事的'WPF方式'是使用数据绑定：

使用名为Text的字符串属性定义一个类。
创建该类的集合。
将列表框ItemsSource绑定到集合。
创建一个DataTemplate，显示一个TextBox，其Text属性使用{Binding Path = Text}进行绑定。
在btnAdd_Click中添加一个项目到集合（不是直接添加到ListBox）
在btnGet_Click中，您可以通过将ListBox.SelectedItem强制转换为您的类并获取其Text属性来获取输入的文本。

示例：

简单的课程：

public class VMObject
{
    public VMObject(string text)
    {
        Text = text;
    }

    public string Text { get; set; }
}

窗口代码隐藏：

public partial class Window1 : Window
{
    public ObservableCollection<VMObject> VM { get; set; }

    public Window1()
    {
        VM = new ObservableCollection<VMObject>();
        InitializeComponent();
    }

    private void btnAdd_Click(object sender, RoutedEventArgs e)
    {
        VM.Add(new VMObject(txtInput.Text));
    }

    private void btnGet_Click(object sender, RoutedEventArgs e)
    {
        if (lb.SelectedItem == null)
            MessageBox.Show("No item is selected!");
        txtReturn.Text = ((VMObject)lb.SelectedItem).Text;
    }
}

XAML：

<Window x:Class="lbtest.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Name="Window"
    Title="Window1" Height="300" Width="300">
    <Window.Resources>
        <DataTemplate x:Key="TextBoxTemplate">
            <TextBox Text="{Binding Path=Text}"/>
        </DataTemplate>
    </Window.Resources>
    <Grid>
        <ListBox Name="lb" Margin="0,0,0,70"
                 ItemsSource="{Binding ElementName=Window, Path=VM}"
                 ItemTemplate="{StaticResource TextBoxTemplate}" />
        <Button Height="23" HorizontalAlignment="Left" Margin="12,0,0,41"
                Name="btnAdd" VerticalAlignment="Bottom"
                Content="Add item" Width="75" Click="btnAdd_Click" />
        <TextBox Height="23" Margin="93,0,12,41"
                 Name="txtInput" VerticalAlignment="Bottom" />
        <Button Height="23" HorizontalAlignment="Left" Margin="12,0,0,12"
                Name="btnGet" VerticalAlignment="Bottom"
                Content="Get value" Width="75" Click="btnGet_Click" />
        <TextBox Height="23" Margin="93,0,12,12"
                 Name="txtReturn" VerticalAlignment="Bottom" IsReadOnly="True" />
    </Grid>
</Window>

Answer 2

表示复选框项目：

private void chk_Checked(object sender, RoutedEventArgs e)
{
    CheckBox chk = (CheckBox)sender;
    MessageBox.Show(chk.Content.ToString()); 
}

Answer 3

不需要TextBox：s。 ListBox句柄很好。

    private void btnAdd_Click(object sender, RoutedEventArgs e)
    {
        // No need to create TextBox, ListBox handle strings fine.
        lb.Items.Add(txtInput.Text);
    }

    private void btnGet_Click(object sender, RoutedEventArgs e)
    {
        // No selection, but button has been pressed.
        if(lb.SelectedItem == -1)
            return;
        // Get selected item.
        txtReturn.Text = (string)lb.SelectedItem;

        /* If you change ListBox selection mode to multiple
         * you can get all selected items by using foreach loop.
        foreach (Object selected in lb.SelectedItems)
        {
            txtReturn.Text +=  (string) selected;
        }
         */
    }

Answer 4

如果您只想获取所选TextBox的Text属性（允许ListBox处于单选模式），那么它非常简单：

private void btnGet_Click(object sender, RoutedEventArgs e)
{
    if(lb.SelectedItem != -1)
    {
        TextBox selectedTextBox = (TextBox)lb.SelectedItem;
        txtReturn.Text = selectedTextBox.Text;
    }
}

但是如果你想实现漂亮的WPF方式，你应该遵循Aviad P.解决方案，我的解决方案也做得很好。

问候。

编辑：如果没有真正需要TextBox功能，但只有一个字符串容器，那么请遵循Tuukka的解决方案。

如何从代码隐藏中访问ListBox动态创建项的属性？

4 个答案: