数据更改在父窗口中反映错误

Question

我有以下要求：

1. 显示TreeView 的项目
2. 在TreeView中显示所选项目的详细信息。
3. 用于编辑所选项目的对话框。

我已经实现了这些要求，但是第三个没有做它应该做的事情，所以我被卡住了。

我想要它做什么： 编辑对话框应该能够编辑项目。这不是TreeViewItem，而是我的一个类的一个实例。

1. 保存编辑 - 一个用于关闭对话框的按钮。
2. 放弃编辑 - 用于重置项目中更改的字段并关闭对话框的按钮。

第二个要求不起作用。如果我编辑一个字段并点击取消，项目详细信息面板仍会显示编辑。我已经调试过，但我发现底层项目没有改变 - 但是项目显示的值已更改。

代码：

1. 物品类别（类别）

   public class Category
   {
       public virtual int Id { get; set; }
       public virtual string Name { get; set; }
       public virtual string Description { get; set; }
       public virtual Unit Unit { get; set; }
       public virtual List<Category> ChildCategories { get; set; }
       public virtual Category ParentCategory { get; set; }
       public virtual bool IsMainCategory { get; set; }
   
       public Category()
       {
           ChildCategories = new List<Category>();
       }
   
       public virtual void AddChild(Category child)
       {
           ChildCategories.Add(child);
           child.ParentCategory = this;
       }
   }
   

2. 项目（类别）详细信息显示在标签中：

   <DataTemplate DataType="{x:Type local:Category}">
       <Grid>
           <Grid.ColumnDefinitions>
               <ColumnDefinition Width="4*" SharedSizeGroup="a" />
               <ColumnDefinition Width="6*" SharedSizeGroup="b" />
           </Grid.ColumnDefinitions>
           <Grid.RowDefinitions>
               <RowDefinition Height="1*" />
               <RowDefinition Height="1*" />
           </Grid.RowDefinitions>
   
           <TextBlock Text="Name" Grid.Column="0" Grid.Row="0" Padding="5"/>
           <TextBlock Text="{Binding Path=Name}" Grid.Column="1" Grid.Row="0" Padding="5"/>
           <TextBlock Text="Description" Grid.Column="0" Grid.Row="1" Padding="5"/>
           <TextBlock Text="{Binding Path=Description}" Grid.Column="1" Grid.Row="1" Padding="5"/>
       </Grid>
   </DataTemplate>
   

3. 主窗口中编辑项目的事件处理程序：

   private void EditCategory(object sender, RoutedEventArgs e)
   {
       Category ctg = _tree.SelectedItem as Category;
       if (ctg != null)
       {
           CategoryDefineWindow cdw = new CategoryDefineWindow();
           cdw.CategoryObject = ctg;
           cdw.ShowDialog();
       }
   }
   

4. 项目编辑器窗口 xaml:

   <Window x:Class="BSRCat.View.CategoryDefineWindow"
       xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
       xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
       Height="150" Width="500">
   <Grid>
       <Grid.ColumnDefinitions>
           <ColumnDefinition Width="3*" SharedSizeGroup="a" />
           <ColumnDefinition Width="7*" SharedSizeGroup="b" />
       </Grid.ColumnDefinitions>
       <Grid.RowDefinitions>
           <RowDefinition Height="1*" />
           <RowDefinition Height="1*" />
           <RowDefinition Height="1*" />
       </Grid.RowDefinitions>
   
       <TextBlock Text="Name" Grid.Column="0" Grid.Row="0" Padding="5"/>
       <TextBox Text="{Binding Path=CategoryObject.Name, RelativeSource={RelativeSource AncestorType=Window}}" Grid.Column="1" Grid.Row="0" Padding="5"/>
       <TextBlock Text="Description" Grid.Column="0" Grid.Row="1" Padding="5"/>
       <TextBox Text="{Binding Path=CategoryObject.Description, RelativeSource={RelativeSource AncestorType=Window}}" Grid.Column="1" Grid.Row="1" Padding="5"/>
   
       <StackPanel Orientation="Horizontal" Grid.Row="2" Grid.ColumnSpan="2" HorizontalAlignment="Right">
           <Button Content="Ok" Margin="5" Height="20" Width="30" Click="Confirmed"/>
           <Button Content="Cancel" Margin="5" Height="20" Width="50" Click="Cancelled"/>
       </StackPanel>
   </Grid>
   </Window>
   

5. 项目编辑器窗口后面的代码：

   public partial class CategoryDefineWindow : Window
   {
       public Category CategoryObject 
       {
           get
           {
           return _category;
           }
           set
           {
               _category = value;
               _initial = new Category() { Name = value.Name, Description = value.Description     };
           }
       }
   
       private Category _category;
       private Category _initial;
   
       public CategoryDefineWindow()
       {
           InitializeComponent();
       }
   
       private void Confirmed(object sender, RoutedEventArgs e)
       {
           Close();
       }
   
       private void Cancelled(object sender, RoutedEventArgs e)
       {
           _category.Name = _initial.Name;
           _category.Description = _initial.Description;
           Close();
       }
   }
   

我已经调试了CategoryDefineWindow.Cancelled 方法并且_category 对象被正确重置。我找不到哪里出错了。

Answer 1

Category 类应该实现 INotifyPropertyChanged 接口。一旦属性值发生更改，WPF 将收到通知。

   public class Category : INotifyPropertyChanged
{
    private string _Name;
    private string _Description;

    public virtual int Id { get; set; }
    public virtual string Name
    {
        get
        {
            return _Name;
        }
        set
        {
            if (_Name == value)
                return;

            _Name = value;
            NotifyPropertyChanged("Name");
        }
    }

    public virtual string Description
    {
        get
        {
            return _Description;
        }
        set
        {
            if (_Description == value)
                return;

            _Description = value;
            NotifyPropertyChanged("Description");
        }
    }
    public virtual Unit Unit { get; set; }
    public virtual List<Category> ChildCategories { get; set; }
    public virtual Category ParentCategory { get; set; }
    public virtual bool IsMainCategory { get; set; }

    public Category()
    {
        ChildCategories = new List<Category>();
    }

    public virtual void AddChild(Category child)
    {
        ChildCategories.Add(child);
        child.ParentCategory = this;
    }

    private void NotifyPropertyChanged(string propertyName)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;
}