数据绑定到数据绑定对象内的列表

Question

我是WPF和数据绑定的新手,所以希望我可以用足够的细节解释我遇到的问题以获得一些帮助.

我有一个绑定到窗口的数据对象列表.让我们说一下食谱清单.我设法让应用程序在列表框中显示每个配方的一些细节,并在各种文本框中显示所选配方的一些更多细节.我的问题是,当我选择食谱时,我想在每个食谱中列出一些成分,我想在另一个列表框中显示,但我无法弄清楚如何使数据绑定起作用.

我的数据类看起来像:

public class Recipes : ObservableCollection<RecipeDetails>
{
}

public class RecipeDetails
{
    public string Name { get; set; }
    public string Description { get; set; }
    public List<RecipeIngredient> Ingredients;
}

public class RecipeIngredient
{
    public string IngredientName { get; set; }
}


public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        m_recipes = new Recipes();
        // m_recipes initialisation
    }

    private void Window_Loaded(object sender, RoutedEventArgs e)
    {
        DataContext = m_recipes;
    }

    private Recipes m_recipes;
}

我的数据绑定尝试(在XAML中)看起来像:

<Window x:Class="RecipeWindow.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Recipe Window" Height="402.687" Width="532.674" Loaded="Window_Loaded">
    <Grid>
        <ListBox Margin="12,58.176,0,16.362" Name="recipeListBox" Width="209.07" IsSynchronizedWithCurrentItem="True" ItemsSource="{Binding}">
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <TextBlock Text="{Binding Name}" FontSize="14" Padding="5" />
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>
        <StackPanel Margin="245.43,58.176,12,47.268" Name="detailsPanel">
            <TextBox Text="{Binding Name,UpdateSourceTrigger=PropertyChanged}" Width="140" />
            <TextBox Text="{Binding Description,UpdateSourceTrigger=PropertyChanged}" Width="140" />
            <ListBox Name="ingredientListBox" Width="209.07" ItemsSource="{Binding Ingredients}" Height="118.17">
                <ListBox.ItemTemplate>
                    <DataTemplate>
                        <TextBlock Text="{Binding IngredientName}" Padding="5" />
                    </DataTemplate>
                </ListBox.ItemTemplate>
            </ListBox>
        </StackPanel>
    </Grid>
</Window>

但是当我尝试运行此代码时,成分列表框始终为空.谁能告诉我我做错了什么？

Answer 1

问题是因为您声明和初始化Ingredients列表的方式,将其设为ObservableCollection并仅在构造函数中初始化Ingredients集合,如下所示

 public class RecipeDetails
{
    public RecipeDetails()
    {
        _ingredients = new ObservableCollection<RecipeIngredient>();
    }

    public string Name { get; set; }
    public string Description { get; set; }

    private ObservableCollection<RecipeIngredient> _ingredients;

    private ObservableCollection<RecipeIngredient> Ingredients
    {
        get { return _ingredients; }
    }
}

还有一点要添加到您的方法中,建议在此类上使用INotifyPropertyChanged,以便在TextBox中键入内容时可以轻松实现TwoWay绑定.