将文本绑定到数组中对象中的嵌套成员
将文本绑定到数组中对象中的嵌套成员
提问于 2019-03-12 08:14:18
我挑战自己让我的应用程序在WPF，我从来没有尝试过:)
也许这是显而易见的，但我不明白我的错误在哪里。
我的RecipePage正确显示part <TextBlock Text="{Binding Name}">，但没有显示<TextBlock Text="{Binding Path=Details[0].PieceName}"> (或1)
我没有错误，只是什么都没有。
是不是由不发送PropertyChanged事件的Recipe.AddDetails()引起的？
提前感谢您的帮助:)
RecipePage.xaml
...
<Grid>
<Button HorizontalAlignment="Left" Width="112" Height="29" VerticalAlignment="Top" Content="PRECEDENT" Margin="10"/>
<StackPanel>
<TextBlock Text="{Binding Name}" Style="{StaticResource h1}"></TextBlock>
<StackPanel Orientation="Horizontal">
<StackPanel>
<TextBlock Text="{Binding Path=Details[0].PieceName}" Style="{StaticResource h2}"></TextBlock>
...
</StackPanel>
<StackPanel>
<TextBlock Text="{Binding Path=Details[1].PieceName}" Style="{StaticResource h2}"></TextBlock>
...
</StackPanel>
</StackPanel>
</StackPanel>
</Grid>
...RecipePage.xaml.cs
public partial class RecipePage : Page
{
public RecipePage(Recipe recipe)
{
InitializeComponent();
DataContext = recipe;
}
}页面创建：
private void OnBourguignonClick(object sender, RoutedEventArgs e)
{
var recipe = new Recipe("BOURGUIGNON ou SAUTE", 190, "images/recipes/rotideboeuf.jpg");
recipe.AddDetails(new RecipeDetails("paleron", 6, 31));
recipe.AddDetails(new RecipeDetails("sauté maigre", 190, 221));
((MainWindow)Application.Current.MainWindow)?.NavigationFrame.NavigationService.Navigate(new RecipePage(recipe));
}Recipe.cs
public class Recipe : INotifyPropertyChanged
{
public string Name { get; set; }
public int MeatWeightPerPers { get; set; }
public string ImagePath { get; set; }
public RecipeDetails[] Details = new RecipeDetails[]{};
public event PropertyChangedEventHandler PropertyChanged;
public Recipe(string name, int meatWeight, string image)
{
Name = name;
MeatWeightPerPers = meatWeight;
ImagePath = image;
}
public void AddDetails(RecipeDetails details)
{
Details.Append(details);
}
}RecipeDetails.cs
public class RecipeDetails : INotifyPropertyChanged
{
public string PieceName { get; set; }
public int PieceWeightPerCow { get; set; }
public int NbPersPerCow { get; set; }
public event PropertyChangedEventHandler PropertyChanged;
public RecipeDetails(string pieceName, int pieceWeightPerCow, int nbPersPerCow)
{
PieceName = pieceName;
PieceWeightPerCow= pieceWeightPerCow;
NbPersPerCow = nbPersPerCow;
}
}FodyWeavers.xml (已安装)
<?xml version="1.0" encoding="utf-8"?>
<Weavers xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="FodyWeavers.xsd">
<PropertyChanged />
</Weavers>回答 1
Stack Overflow用户
回答已采纳
发布于 2019-03-12 09:25:32
主要问题是向Details添加元素不会引发CollectionChanged事件。此事件在更改时由ObservableCollection自动引发，因此您需要使用该事件而不是数组：
public class Recipe : INotifyPropertyChanged
{
public string Name { get; set; }
public int MeatWeightPerPers { get; set; }
public string ImagePath { get; set; }
// Instead of array, use ObservableCollection
public ObservableCollection<RecipeDetails> Details { get; set; }
public event PropertyChangedEventHandler PropertyChanged;
public Recipe(string name, int meatWeight, string image)
{
Name = name;
MeatWeightPerPers = meatWeight;
ImagePath = image;
// Initialize Details collection
Details = new ObservableCollection<RecipeDetails>();
}
public void AddDetails(RecipeDetails details)
{
Details.Add(details);
}
}由于Details是某种类型的列表，因此您可能希望使用ItemsControl而不是单个TextBlock来显示它：
...
<Grid>
<Button HorizontalAlignment="Left" Width="112" Height="29" VerticalAlignment="Top" Content="PRECEDENT" Margin="10"/>
<StackPanel>
<TextBlock Text="{Binding Name}" Style="{StaticResource h1}"></TextBlock>
<StackPanel Orientation="Horizontal">
<ItemsControl ItemsSource="{Binding Details}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<StackPanel>
<TextBlock Text="{Binding PieceName}" Style="{StaticResource h2}" />
...
</StackPanel>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</StackPanel>
</StackPanel>
</Grid>
...页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/55112249
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