来自同一来源的2个不同过滤的绑定，得出相同的结果（WPF）

Question

所以，我创建了一个示例来显示我目前在WPF应用程序中遇到的问题。首先，我有一个餐馆对象，包含名称，以及我打算绑定到CheckBox.Checked值的选定变量。我将它附加到ComboBox和ListBox作为其ItemsSource。

public class Restaurants
{
    public String Name { get; set; }
    public Boolean Selected { get; set; }
}

rItems = new List<Restaurants>();
rItems.Add(new Restaurants() { Name = "Alice Fazoolis", Selected = false });
rItems.Add(new Restaurants() { Name = "Applebees", Selected = false });
rItems.Add(new Restaurants() { Name = "Caseys", Selected = false });
rItems.Add(new Restaurants() { Name = "Cracker Barrell", Selected = false }); 
rItems.Add(new Restaurants() { Name = "East Side Marios", Selected = false });
rItems.Add(new Restaurants() { Name = "Golden Griddle", Selected = false });
rItems.Add(new Restaurants() { Name = "Harveys", Selected = true });
rItems.Add(new Restaurants() { Name = "Imperial Buffet", Selected = false });
rItems.Add(new Restaurants() { Name = "Jack Astors", Selected = false });
rItems.Add(new Restaurants() { Name = "Kakimono", Selected = false });
rItems.Add(new Restaurants() { Name = "Kelseys", Selected = false });
rItems.Add(new Restaurants() { Name = "Little Ceasars", Selected = false });
rItems.Add(new Restaurants() { Name = "Lonestar", Selected = false });
rItems.Add(new Restaurants() { Name = "Makimono", Selected = false });
rItems.Add(new Restaurants() { Name = "Mandarin", Selected = false });
rItems.Add(new Restaurants() { Name = "McDonalds", Selected = false });
rItems.Add(new Restaurants() { Name = "Milestones", Selected = false });
rItems.Add(new Restaurants() { Name = "Montanas", Selected = false });
rItems.Add(new Restaurants() { Name = "Moxies", Selected = false });
rItems.Add(new Restaurants() { Name = "Mr. Sub", Selected = false });
rItems.Add(new Restaurants() { Name = "None", Selected = false });
rItems.Add(new Restaurants() { Name = "Other (Specify)", Selected = false });
rItems.Add(new Restaurants() { Name = "Pizza Pizza", Selected = false });
rItems.Add(new Restaurants() { Name = "Spring Rolls", Selected = false });
rItems.Add(new Restaurants() { Name = "Subway", Selected = false });
rItems.Add(new Restaurants() { Name = "St. Louis Bar & Grill", Selected = false });
rItems.Add(new Restaurants() { Name = "Sunset Grill", Selected = false });
rItems.Add(new Restaurants() { Name = "Swiss Chalet", Selected = false });
rItems.Add(new Restaurants() { Name = "Tatemono", Selected = false });
rItems.Add(new Restaurants() { Name = "The Keg", Selected = false });
rItems.Add(new Restaurants() { Name = "The Melting Pot", Selected = false });
rItems.Add(new Restaurants() { Name = "The Outback", Selected = false });
rItems.Add(new Restaurants() { Name = "Tim Hortons", Selected = false });
rItems.Add(new Restaurants() { Name = "Wendys", Selected = false });
rItems.Add(new Restaurants() { Name = "Wimpys Diner", Selected = false });
rItems.Add(new Restaurants() { Name = "Quiznos", Selected = false });
cboSelections.ItemsSource = rItems;
lstAnswers.ItemsSource = rItems;

然后我有两种过滤方法。一个用于选择以特定字母开头的所有值，第二个用于获取所有选定的项目。在我的屏幕上，我生成了每个起始字母的键盘。选择一个字母后，我会过滤列表并仅显示这些结果。选定的组将被放入ListBox

private bool LetterFilter(object item){
    if (((Restaurants) item).Name.ToUpper().StartsWith(LetterClicked))
        return true;
    else
        return false;
}

private bool SelectedFilter(object item){
    if (((Restaurants)item).Selected)
        return true;
    else
        return false;
 }

当Window_Loaded时，我根据一封我已知不会对ListBox产生任何结果的信件进行过滤。并告诉我的选择框以获取任何选定的值。 （我希望启动时屏幕为空）

private void Window_Loaded(object sender, RoutedEventArgs e)
{
    CollectionView viewCBO = (CollectionView)CollectionViewSource.GetDefaultView(cboSelections.ItemsSource);
    viewCBO.Filter = SelectedFilter;
    CollectionView viewLST = (CollectionView)CollectionViewSource.GetDefaultView(lstAnswers.ItemsSource);
    LetterClicked = "-";
    viewLST.Filter = LetterFilter;
}`

private void btnLetter_Click(object sender, RoutedEventArgs e)
{
    CollectionView view = (CollectionView)CollectionViewSource.GetDefaultView(lstAnswers.ItemsSource);
    LetterClicked = ((Button)sender).Content.ToString();
    view.Filter = LetterFilter;
}

问题是，当我加载任何一个过滤器时，我最终在viewCBO和viewLST中获得相同的值。因此，例如，如果我选择“L”，我会看到两个中的“小凯撒”和“孤星”，尽管没有选择任何一个。

我需要的是viewLST使我的答案列表的值按字母过滤，而viewCBO则为所有Selected = true的单独列表。但是来自同一个来源。

感谢所有帮助：）

Answer 1

如果对CollectionViewSource使用具有相同列表的静态方法，它将具有相同的源。请参阅以下代码。

<Window x:Class="MSDN15Jan2015_Learning.Window4"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window4" Height="600" Width="300">
<StackPanel> 
    <TextBox x:Name="txt" Height="20" Width="200"/>
    <Button x:Name="btn" Click="btn_Click" Content="Letter Refresh"/>
   <ListBox x:Name="lstAnswers" Height="200" SelectionMode="Multiple" SelectionChanged="lstAnswers_SelectionChanged">
        <ListBox.ItemContainerStyle>
            <Style TargetType="{x:Type ListBoxItem}">
                <Setter Property="IsSelected" Value="{Binding Selected}"/>
            </Style>
        </ListBox.ItemContainerStyle>
        <ListBox.ItemTemplate>
            <DataTemplate>
                <StackPanel Orientation="Horizontal">
                    <TextBlock Text="{Binding Name}"/>
                    <CheckBox IsChecked="{Binding Selected}"/>
                </StackPanel>
            </DataTemplate>
        </ListBox.ItemTemplate>
    </ListBox>
    <ComboBox DisplayMemberPath="Name" x:Name="cboSelections" Height="20"/>
</StackPanel>

  using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;

namespace MSDN15Jan2015_Learning
{
    /// <summary>
    /// Interaction logic for Window4.xaml
    /// </summary>
    public partial class Window4 : Window
    {
        ObservableCollection<Restaurants> rItems;
        string LetterClicked;
        public Window4()
        {
            InitializeComponent();
            this.Loaded += Window4_Loaded;
            rItems = new ObservableCollection<Restaurants>();
            rItems.Add(new Restaurants() { Name = "Alice Fazoolis", Selected = false });
            rItems.Add(new Restaurants() { Name = "Applebees", Selected = false });
            rItems.Add(new Restaurants() { Name = "Caseys", Selected = false });
            rItems.Add(new Restaurants() { Name = "Cracker Barrell", Selected = false });
            rItems.Add(new Restaurants() { Name = "East Side Marios", Selected = false });
            rItems.Add(new Restaurants() { Name = "Golden Griddle", Selected = false });
            rItems.Add(new Restaurants() { Name = "Harveys", Selected = false });
            rItems.Add(new Restaurants() { Name = "Imperial Buffet", Selected = false });
            rItems.Add(new Restaurants() { Name = "Jack Astors", Selected = false });
            rItems.Add(new Restaurants() { Name = "Kakimono", Selected = false });
            rItems.Add(new Restaurants() { Name = "Kelseys", Selected = false });
            rItems.Add(new Restaurants() { Name = "Little Ceasars", Selected = false });
            rItems.Add(new Restaurants() { Name = "Lonestar", Selected = false });
            rItems.Add(new Restaurants() { Name = "Makimono", Selected = false });
            rItems.Add(new Restaurants() { Name = "Mandarin", Selected = false });
            rItems.Add(new Restaurants() { Name = "McDonalds", Selected = false });
            rItems.Add(new Restaurants() { Name = "Milestones", Selected = false });
            rItems.Add(new Restaurants() { Name = "Montanas", Selected = false });
            rItems.Add(new Restaurants() { Name = "Moxies", Selected = false });
            rItems.Add(new Restaurants() { Name = "Mr. Sub", Selected = false });
            rItems.Add(new Restaurants() { Name = "None", Selected = false });
            rItems.Add(new Restaurants() { Name = "Other (Specify)", Selected = false });
            rItems.Add(new Restaurants() { Name = "Pizza Pizza", Selected = false });
            rItems.Add(new Restaurants() { Name = "Spring Rolls", Selected = false });
            rItems.Add(new Restaurants() { Name = "Subway", Selected = false });
            rItems.Add(new Restaurants() { Name = "St. Louis Bar & Grill", Selected = false });
            rItems.Add(new Restaurants() { Name = "Sunset Grill", Selected = false });
            rItems.Add(new Restaurants() { Name = "Swiss Chalet", Selected = false });
            rItems.Add(new Restaurants() { Name = "Tatemono", Selected = false });
            rItems.Add(new Restaurants() { Name = "The Keg", Selected = false });
            rItems.Add(new Restaurants() { Name = "The Melting Pot", Selected = false });
            rItems.Add(new Restaurants() { Name = "The Outback", Selected = false });
            rItems.Add(new Restaurants() { Name = "Tim Hortons", Selected = false });
            rItems.Add(new Restaurants() { Name = "Wendys", Selected = false });
            rItems.Add(new Restaurants() { Name = "Wimpys Diner", Selected = false });
            rItems.Add(new Restaurants() { Name = "Quiznos", Selected = false });           
        }
        ICollectionView viewCBO;
        ICollectionView viewLST;
        void Window4_Loaded(object sender, RoutedEventArgs e)
        {
            viewCBO = new CollectionViewSource { Source = rItems }.View;
            viewCBO.Filter = SelectedFilter;
            viewLST = new CollectionViewSource { Source = rItems }.View;
            LetterClicked = "-";
            viewLST.Filter = LetterFilter;
            cboSelections.ItemsSource = viewCBO;
            lstAnswers.ItemsSource = viewLST;
        }
        private bool LetterFilter(object item)
        {
            if (((Restaurants)item).Name.ToUpper().StartsWith(LetterClicked))
                return true;
            else
                return false;
        }

        private bool SelectedFilter(object item)
        {
            if (((Restaurants)item).Selected)
                return true;
            else
                return false;
        }

        private void btn_Click(object sender, RoutedEventArgs e)
        {   
            LetterClicked =txt.Text;
            viewLST.Filter = null;
            viewLST.Filter = LetterFilter;
            viewLST.Refresh();
        }

        private void lstAnswers_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            viewCBO.Refresh();
        }
    }

    public class Restaurants:INotifyPropertyChanged
    {
        private string name;

        public string Name
        {
            get { return name; }
            set { name = value; OnNotify("Name"); }
        }

        private bool selected;

        public bool Selected
        {
            get { return selected; }
            set { selected = value; OnNotify("Selected"); }
        }

        public event PropertyChangedEventHandler PropertyChanged;

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


}