所選項目不在另一個列表框項目模板中獲取列表框

Question

我有一個PrimaryItems列表＆foreach PrimaryItem有一個SecondaryItems ListBox 。所以我使用了一個ListBox作為另一個ListBox ItempTemplate 。

<ListBox ItemsSource="{Binding PrimaryItems}">
        <ListBox.ItemTemplate>
            <DataTemplate>
                <StackPanel>
                    <TextBlock Text="{Binding Name}"/>
                    <ListBox ItemsSource="{Binding SecondaryItems}" SelectedItem="{Binding SelectedSecondaryItem}" ScrollViewer.VerticalScrollBarVisibility="Disabled" ScrollViewer.HorizontalScrollBarVisibility="Disabled">
                        <ListBox.ItemTemplate>
                            <DataTemplate>
                                <TextBlock Text="{Binding Name}"/>
                            </DataTemplate>
                        </ListBox.ItemTemplate>
                    </ListBox>
                </StackPanel>
            </DataTemplate>
        </ListBox.ItemTemplate>
    </ListBox>

我的視圖模型代碼

    private List<PrimaryItem> _primaryItems;
    public List<PrimaryItem> PrimaryItems
    {
        get { return _primaryItems; }
        set { _primaryItems = value;RaisePropertyChanged(); }
    }

    //SecondaryItems list is inside in each PrimaryItem
    //private List<SecondaryItem> _secondaryItems;
    //public List<SecondaryItem> SecondaryItems
    //{
       // get { return _secondaryItems; }
       // set { _secondaryItems = value; RaisePropertyChanged(); }
    //}

    private SecondaryItem _selectedSecondaryItem;
    public SecondaryItem SelectedSecondaryItem
    {
        get { return _selectedSecondaryItem; }
        set 
        {
            _selectedSecondaryItem = value;
            if (_selectedSecondaryItem != null)
            {
                //TO DO
            }
        }
    }<br/>

這是class結構

public class PrimaryItem
{
  public int Id { get; set; }
  public string Name { get; set; }
  public List<SecondaryItem> SecondaryItems{ get; set; }
}

public class SecondaryItem
{
  public int Id { get; set; }
  public string Name { get; set; }  
}

我將SelectedItem Binding設置為Second ListBox 。
但是沒有在Second ListBox上獲得選擇觸發器。
我們可以在另一個ListBox模板中使用ListBox嗎？
如果是，我們如何克服這個問題？

Answer 1

首先，使用ObservableCollection而不是List因為它實現了INotifyPropertyChanged接口。

據我了解您的要求， PrimaryItem類應具有屬性SecondaryItems 。 因此，將其從ViewModel刪除並粘貼到PrimaryItem類（以及SelectedSecondaryItem屬性）：

private ObservableCollection<SecondaryItem> _secondaryItems;
public ObservableCollection<SecondaryItem> SecondaryItems
{
    get { return _secondaryItems; }
    set { _secondaryItems = value; RaisePropertyChanged(); }
}

編輯：

我已完全復制了您的情況並使其正常運行。

類：

public class PrimaryItem
{
    public int Id { get; set; }
    public string Name { get; set; }
    public List<SecondaryItem> SecondaryItems { get; set; }

    private SecondaryItem _selectedSecondaryItem;
    public SecondaryItem SelectedSecondaryItem
    {
        get { return _selectedSecondaryItem; }
        set
        {
            _selectedSecondaryItem = value;

            if (_selectedSecondaryItem != null)
            { // My breakpoint here
                //TO DO
            }
        }
    }
}

public class SecondaryItem
{
    public int Id { get; set; }
    public string Name { get; set; }
}

ViewModel：

public class MyViewModel : ViewModelBase
{
    private List<PrimaryItem> _primaryItems;
    public List<PrimaryItem> PrimaryItems
    {
        get { return _primaryItems; }
        set { _primaryItems = value; RaisePropertyChanged("PrimaryItems"); }
    }

    public ErrorMessageViewModel()
    {
        this.PrimaryItems = new List<PrimaryItem>
            {
                new PrimaryItem
                    {
                        SecondaryItems =
                            new List<SecondaryItem>
                                {
                                    new SecondaryItem { Id = 1, Name = "First" },
                                    new SecondaryItem { Id = 2, Name = "Second" },
                                    new SecondaryItem { Id = 3, Name = "Third" }
                                },
                        Name = "FirstPrimary",
                        Id = 1
                    }
            };
    }
}

視圖：

<Window x:Class="TestApp.Views.MyView"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:vm="clr-namespace:TestApp.ViewModels;assembly=TestApp.ViewModels"
    xmlns:my="http://schemas.microsoft.com/wpf/2008/toolkit"
    Title="Title" Height="240" Width="270" ResizeMode="NoResize"
    WindowStartupLocation="CenterOwner" WindowStyle="ToolWindow">
<Window.DataContext>
    <vm:MyViewModel/>
</Window.DataContext>
<Grid>
    <ListBox ItemsSource="{Binding PrimaryItems}">
        <ListBox.ItemTemplate>
            <DataTemplate>
                <StackPanel>
                    <TextBlock Text="{Binding Name}"/>
                    <ListBox ItemsSource="{Binding SecondaryItems}" SelectedItem="{Binding SelectedSecondaryItem}" ScrollViewer.VerticalScrollBarVisibility="Disabled" ScrollViewer.HorizontalScrollBarVisibility="Disabled">
                        <ListBox.ItemTemplate>
                            <DataTemplate>
                                <TextBlock Text="{Binding Name}"/>
                            </DataTemplate>
                        </ListBox.ItemTemplate>
                    </ListBox>
                </StackPanel>
            </DataTemplate>
        </ListBox.ItemTemplate>
    </ListBox>
</Grid>
</Window>

Answer 2

您可以嘗試使用LinqToVisualTree ，它可以在您的應用程序中獲取幾乎所有Control ，您只需要選擇要查找的內容（在您的情況下為ListBoxItem ），然后將其轉換為模型即可。 我需要從ListboxItem TextBox獲取文本時使用它。 但這也適合您的任務。