WPF嵌套列表性能問題

Question

下面的代碼有第二個組合框的性能問題......當我改變第一個combox然後打開第二個combox時它是好的。但是，如果我改變了第二次的第一COMBOX並嘗試打開它有很多性能問題的 第二COMBOX箱....

公共部分類主窗口：窗口， INotifyPropertyChanged的 {

public MainWindow() 
    { 
     InitializeComponent(); 

     Books = new List<Book>(); 
     Books.Add(new Book("Abc")); 
     Books.Add(new Book("Cde")); 
     Books.Add(new Book("Xyz")); 
     Books.Add(new Book("Min")); 
     this.DataContext = this; 
     SelectedBook = Books[0]; 
    } 

    Book _selctedBook; 
    public Book SelectedBook 
    { 
     get { return _selctedBook; } 
     set 
     { 
      _selctedBook = value; 
      raiseChange("SelectedBook"); 
     } 
    } 

    List<Book> _books = new List<Book>(); 
    public List<Book> Books { get { return _books; } set { _books = value; raiseChange("Books"); } } 

    void raiseChange(string name) 
    { 
     if (PropertyChanged != null) 
      PropertyChanged(this, new PropertyChangedEventArgs(name)); 
    } 

    public event PropertyChangedEventHandler PropertyChanged; 

} 

public class Book : INotifyPropertyChanged 
{ 
    public string Name { get; set; } 
    public ObservableCollection<BookType> BookTypes { get; set; } 

    BookType _selectedBookType; 
    public BookType SelectedBookType { get { return _selectedBookType; } set { _selectedBookType = value; raiseChange("SelectedBookType"); } } 

    public Book(string name) 
    { 
     Name = name; 
     BookTypes = new ObservableCollection<BookType>(); 


     if (name == "Abc") 
      BookTypes.Add(BookType.Action); 

     BookTypes.Add(BookType.Comedy); 
     BookTypes.Add(BookType.Drama); 
     BookTypes.Add(BookType.Friction); 
     BookTypes.Add(BookType.Thriller); 

     SelectedBookType = BookTypes[0]; 
    } 


     void raiseChange(string name) 
    { 
     if (PropertyChanged != null) 
      PropertyChanged(this, new PropertyChangedEventArgs(name)); 
    } 

    public event PropertyChangedEventHandler PropertyChanged; 
} 

public enum BookType 
{ 
    Friction, 
    Drama, 
    Action, 
    Thriller, 
    Comedy, 
} 

<Grid> 
    <Grid.Resources> 
     <DataTemplate x:Key="ItemTemplate2"> 
      <StackPanel> 
       <TextBlock Text="{Binding .}"/> 
      </StackPanel> 
     </DataTemplate> 
    </Grid.Resources> 
    <Grid.RowDefinitions> 
     <RowDefinition></RowDefinition> 
     <RowDefinition></RowDefinition> 
    </Grid.RowDefinitions> 
     <ComboBox Height="23" Name="comboBox1" Grid.Row="0" 
       SelectedItem="{Binding SelectedBook,Mode=TwoWay}" 
       ItemsSource="{Binding Books}" 
       DisplayMemberPath="Name" 
       Width="386" /> 
    <ComboBox Height="23" Name="comboBox2" Grid.Row="1" DataContext="{Binding SelectedItem, ElementName=comboBox1}" 
       ItemsSource="{Binding BookTypes}" SelectedItem="{Binding SelectedBookType,Mode=TwoWay}" 
       Width="386" ItemTemplate="{DynamicResource ItemTemplate2}"> 

    </ComboBox> 

</Grid> 

Answer 1

我懷疑它與每次第一個盒子更改時重新綁定第二枚枚舉有關。

取而代之，綁定第二個盒子一次;

 <Grid.Resources> 
      <DataTemplate x:Key="ItemTemplate2"> 
       <StackPanel> 
        <TextBlock Text="{Binding .}"/> 
       </StackPanel> 
      </DataTemplate> 

      <ObjectDataProvider x:Key="BookTypeEnum" MethodName="GetValues" ObjectType="{x:Type System:Enum}"> 
       <ObjectDataProvider.MethodParameters> 
        <x:Type TypeName="local:BookType"/> 
       </ObjectDataProvider.MethodParameters> 
      </ObjectDataProvider> 

     </Grid.Resources> 


    <ComboBox Height="23" Name="comboBox2" Grid.Row="1" DataContext="{Binding SelectedItem, ElementName=comboBox1}" 
      ItemsSource="{Binding Source={StaticResource BookTypeEnum}}" SelectedItem="{Binding SelectedBookType,Mode=TwoWay}" 
      Width="386" />