过滤CollectionViewSource [英] Filtering CollectionViewSource

问题描述

我想通过过滤器将一个 ComboBox 绑定到我的数据。为此，我创建了一个 TextBox 和一个 ComboBox 。在后面的代码中，我读取一个文件，并生成存储为 ComboBox 项目的类Channel的对象。虽然编译器没有发出错误，但是过滤不能正常工作。如果我写的东西数据不见了，如果我擦除，它回来了。尝试和尝试后，我意识到，如果我开始输入myNamespace.myChannel（Unico.Canal），数据仍然保留，但不要过滤。奇怪的行为，的确。我怀疑我把东西放在错误的地方。

（为了更好地理解我已经翻译了代码，Canal = Channel） >

这是我的代码的方案：

 命名空间Unico 
 {
 public partial class ControlesArchivo：UserControl，INotifyPropertyChanged 
 {
 public ControlesArchivo（）
 {
 
 InitializeComponent（）; 
} 
 
 public ObservableCollection< Channel> myListChannels //与INotifyPropertyChanged实现。但我认为我不需要它。 
 
 private void loadButton_Click（object sender，RoutedEventArgs e）
 {
 
文件loadedFile = new File（）; 
 loadedFile.read（）; //在列表中生成一堆数据。 
 
 foreach（Channel mychan in loadedFile.channels）//只是复制数据（也许这可以避免）
 {
 myListChannels.Add（mychan）; 
} 
 
 var view = CollectionViewSource.GetDefaultView（this.miListaDeCanales）; 
 view.Filter = delegate（object o）
 {
 if（o.ToString（）。包含（myTextBox.Text））//精致的地方
 {
返回真
} 
返回false; 
}; 
 
 myComboBox.ItemsSource = view; 
 DataContext = this; 
} 
 
 
 private void myTextBox_TextChanged（object sender，TextChangedEventArgs e）
 {
 
 
（（ICollectionView）myComboBox。 ItemsSource）.Refresh（）; 
 myComboBox.SelectedIndex = 0; 
 
} 
 
 
} 
} 
  

数据绑定在XAML中：

  ItemsSource ={Binding view}
  

编辑：我想我知道问题在哪里：我没有指定要过滤的属性。我的意思是，您在ComboBox中看到的是myListChannels中列出的类Channel 的属性 channelName 。当我设置过滤器时，不应该知道我在过滤什么？我该怎么写这个？非常感谢。

解决方案

是你的假设是正确的。

我假设你的翻译，

  public ObservableCollection< Channel> myListChannels; 
  

实际上是

 code> public ObservableCollection< Canal> miListaDeCanales; 
  

与命名空间中的 Canal code> Unico

更新：

在过滤器中，尝试使用 ComboBox 中呈现的属性，而不是使用 ToString（） code> object （ o ）如果您没有覆盖 ToString（）从 System.Object 。

尝试切换

  if（o.ToString（）。包含（myTextBox.Text）
  

$ b $如果（（（Canal）o）.NameProperty.Contains（myTextBox.Text））

$ b

  b  

^^应该解决您的问题。

您在xaml中的 ComboBox.ItemTemplate 有一个 DataTemplate 。这将解释为什么你看到在 ComboBox 中呈现的有效值，否则所有的 ComboBoxItem 也将呈现为 Unico.Canal

I want to make a ComboBox bound to my data, with a filter. For that I've created a TextBox and a ComboBox. In the code behind I read a file and generate objects of class Channel that are stored as items of the ComboBox. Although the compiler throws no error the filtering doesn't work properly. If I write something the data is gone, if I erase, it's back. After trying and trying I've realized that if I started typing "myNamespace.myChannel" (Unico.Canal) the data remained, but don't filter. Strange behaviour, indeed. I suspect that I've put something in wrong place.

(for better understanding I've translated the code, Canal=Channel)

Here is the scheme of my code:

namespace Unico
{
        public partial class ControlesArchivo : UserControl, INotifyPropertyChanged
        {
            public ControlesArchivo()
            {

                InitializeComponent();        
            }

    public ObservableCollection<Channel> myListChannels //with INotifyPropertyChanged implemented. But I think I don't need it.

     private void loadButton_Click(object sender, RoutedEventArgs e)
            {

              File loadedFile = new File();
              loadedFile.read(); //Generates a bunch of data in lists.

              foreach (Channel mychan in loadedFile.channels) //Just duplicating the data (maybe this can be avoided)
                   {
                    myListChannels.Add(mychan);
                   }

         var view = CollectionViewSource.GetDefaultView(this.miListaDeCanales);
                        view.Filter = delegate(object o)
                        {
                            if (o.ToString().Contains(myTextBox.Text)) //Delicate place
                            {
                                return true;
                            }
                            return false;
                        };

                myComboBox.ItemsSource = view;
     DataContext = this;
    }


     private void myTextBox_TextChanged(object sender, TextChangedEventArgs e)
            {


                       ((ICollectionView)myComboBox.ItemsSource).Refresh();
                       myComboBox.SelectedIndex = 0;

            }


      }
    }

The data is bound in XAML with:

 ItemsSource="{Binding view}" 

EDIT: I think I know where is the problem: I'm not specifing the property to filter. I mean, what you see in the ComboBox is the property channelName of the class Channel listed in myListChannels. When I'm setting the filter, shouldn't I let know what I'm filtering? How could I write this? Thank you very much.

解决方案

Yes your assumption is correct.

I'm assuming with your translations,

public ObservableCollection<Channel> myListChannels;

is actually

public ObservableCollection<Canal> miListaDeCanales;

with the class Canal in the namespace Unico

Update:

In your filter try using the property that is rendered in the ComboBox than use the ToString() on the object(o) if you've not overridden ToString() from System.Object.

try switching

if (o.ToString().Contains(myTextBox.Text))

to

if (((Canal)o).NameProperty.Contains(myTextBox.Text))

^^ that should fix your issue.

Do you have a DataTemplate for ComboBox.ItemTemplate in xaml. That will explain why you see the valid value rendered in the ComboBox, else all the ComboBoxItem's will also render as Unico.Canal

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