Question

我面临一个奇怪的问题。我在XAML程序中创建了两个用作ViewModel的类。这两个类非常相似，但其中一个没有将“属性更改”事件传递给UI。在这两种情况下，我都使用绑定TwoWay。我尝试在同一个UI中为另一个类更改一个类，MovieGroup最终起作用，但不是MovieDataItem（意味着绑定的XAML声明被证明有效）

以下是课程：

 public class MovieDataItem : DependencyObject
{
    public MovieDataItem(String uniqueId, String title, String subtitle, String imagePath, String description, String content)
    {
        this.UniqueId = uniqueId;
        this.Title = title;
        this.Subtitle = subtitle;
        this.Description = description;
        this.ImagePath = imagePath;
        this.Content = content;
    }

    public MovieDataItem(MovieDataItem other)
    {
        UniqueId = other.UniqueId;
        Title = other.Title;
        Subtitle = other.Subtitle;
        Description = other.Description;
        ImagePath = other.ImagePath;
        Content = other.Content;
    }

    public string UniqueId { get; set; }

    public String Title
    {
        get { return (String)this.GetValue(TitleProperty); }
        set { this.SetValue(TitleProperty, value); }
    }
    public static readonly DependencyProperty TitleProperty = DependencyProperty.Register(
      "Title", typeof(String), typeof(MovieDataItem), new PropertyMetadata(false));

    public String Subtitle
    {
        get { return (String)this.GetValue(SubtitleProperty); }
        set { this.SetValue(SubtitleProperty, value); }
    }
    public static readonly DependencyProperty SubtitleProperty = DependencyProperty.Register(
      "Subtitle", typeof(String), typeof(MovieDataItem), new PropertyMetadata(false));

    public String Description
    {
        get { return (String)this.GetValue(DescriptionProperty); }
        set { this.SetValue(DescriptionProperty, value); }
    }
    public static readonly DependencyProperty DescriptionProperty = DependencyProperty.Register(
      "Description", typeof(String), typeof(MovieDataItem), new PropertyMetadata(false));

    public String Content
    {
        get { return (String)this.GetValue(ContentProperty); }
        set { this.SetValue(ContentProperty, value); }
    }
    public static readonly DependencyProperty ContentProperty = DependencyProperty.Register(
      "Content", typeof(String), typeof(MovieDataItem), new PropertyMetadata(false));

    public String ImagePath
    {
        get { return (String)this.GetValue(ImagePathProperty); }
        set { this.SetValue(ImagePathProperty, value); }
    }
    public static readonly DependencyProperty ImagePathProperty = DependencyProperty.Register(
      "ImagePath", typeof(String), typeof(MovieDataItem), new PropertyMetadata(false));

    public override string ToString()
    {
        return this.Title;
    }

    public void CopyTo(MovieDataItem other)
    {
        other.UniqueId = UniqueId;
        other.Title = Title;
        other.Subtitle = Subtitle;
        other.Description = Description;
        other.ImagePath = ImagePath;
        other.Content = Content;
    }
}

/// <summary>
/// Generic group data model.
/// </summary>
public class MovieGroup : DependencyObject
{
    public MovieGroup(String uniqueId, String title, String subtitle, String imagePath, String description)
    {
        this.UniqueId = uniqueId;
        this.Title = title;
        this.Subtitle = subtitle;
        this.Description = description;
        this.ImagePath = imagePath;
        this.Items = new ObservableCollection<MovieDataItem>();
    }

    public MovieGroup(MovieGroup other)
    {
        UniqueId = other.UniqueId;
        Title = other.Title;
        Subtitle = other.Subtitle;
        Description = other.Description;
        ImagePath = other.ImagePath;
        Items = other.Items;
    }

    public string UniqueId { get; set; }


    public ObservableCollection<MovieDataItem> Items
    {
        get { return (ObservableCollection<MovieDataItem>)this.GetValue(ItemsProperty); }
        set { this.SetValue(ItemsProperty, value); }
    }
    public static readonly DependencyProperty ItemsProperty = DependencyProperty.Register(
      "Items", typeof(ObservableCollection<MovieDataItem>), typeof(MovieGroup), new PropertyMetadata(false));

    public String Title
    {
        get { return (String)this.GetValue(TitleProperty); }
        set { this.SetValue(TitleProperty, value); }
    }
    public static readonly DependencyProperty TitleProperty = DependencyProperty.Register(
      "Title", typeof(String), typeof(MovieGroup), new PropertyMetadata(false));

    public String Subtitle
    {
        get { return (String)this.GetValue(SubtitleProperty); }
        set { this.SetValue(SubtitleProperty, value); }
    }
    public static readonly DependencyProperty SubtitleProperty = DependencyProperty.Register(
      "Subtitle", typeof(String), typeof(MovieGroup), new PropertyMetadata(false));

    public String Description
    {
        get { return (String)this.GetValue(DescriptionProperty); }
        set { this.SetValue(DescriptionProperty, value); }
    }
    public static readonly DependencyProperty DescriptionProperty = DependencyProperty.Register(
      "Description", typeof(String), typeof(MovieGroup), new PropertyMetadata(false));

    public String ImagePath
    {
        get { return (String)this.GetValue(ImagePathProperty); }
        set { this.SetValue(ImagePathProperty, value); }
    }
    public static readonly DependencyProperty ImagePathProperty = DependencyProperty.Register(
      "ImagePath", typeof(String), typeof(MovieGroup), new PropertyMetadata(false));

    public override string ToString()
    {
        return this.Title;
    }

    public void CopyTo(MovieGroup other)
    {
        other.UniqueId = UniqueId;
        other.Title = Title;
        other.Subtitle = Subtitle;
        other.Description = Description;
        other.ImagePath = ImagePath;
        other.Items = Items;
    }
}

其他信息：

DataContext设置如下：

DataContext="{Binding DefaultViewModel, RelativeSource={RelativeSource Self}}"

，对象如下：

ObservableDictionary defaultViewModel = new ObservableDictionary();

然后，我将我的电影组和项目添加到字典中。出于测试目的，我只使用了一个xaml表单并在两个对象之间交替（它们具有我可以使用的公共属性名称）。它是这样的：

//C#; Adding Group to the dictionary
MovieGroup group = new MovieGroup(Guid.NewGuid().ToString(), "My Category", String.Empty, String.Empty, "Description");

DefaultViewModel.Add("Group", group);

现在XAML：

<TextBlock Text="{Binding Group.Title, Mode=TwoWay}" 
           Foreground="{StaticResource ListViewItemOverlayForegroundThemeBrush}"
           Style="{StaticResource BaseTextBlockStyle}" 
           Height="60" 
           Margin="15,0,15,0" 
           FontWeight="SemiBold"/>
<TextBlock Text="{Binding Group.Subtitle}" 
           Foreground="{StaticResource ListViewItemOverlaySecondaryForegroundThemeBrush}" 
           Style="{StaticResource BaseTextBlockStyle}" 
           TextWrapping="NoWrap" 
           Margin="15,0,15,10" 
           FontSize="12"/>

这很有效。但是，如果我将数据源更改为使用MovieDataItem，而不更改任何其他内容，则它不起作用;

我改变了电影组。由于两者都具有Title和Subtitle属性，因此我无需进行任何更改：

MovieDataItem movie = new MovieDataItem(Guid.NewGuid().ToString(), "My Movie", "Subtitle", String.Empty, "Description", String.Empty);

DefaultViewModel.Add("Group", movie);

C＃DependencyProperty绑定无法正常工作

0 个答案: