Question

您已创建一个绑定到计算机列表的列表框。随着机器数量的急剧增加，我需要以某种方式按名称进行过滤。出于这个原因，我提供了一个TextBox，用户可以在其中引入一个字符串来过滤掉。我曾想过创建另一个列表，它将绑定到视图，即第二个列表，仅用于可视化。但是，我认为必须有一个更清洁的方法来做到这一点。

<ListBox  IsSynchronizedWithCurrentItem="True" Visibility="{Binding MachinesPanelVisibility}" 
                    ItemsSource="{Binding MachineRulesList}" SelectedIndex="{Binding ItemSelectionIndex}" />

 <TextBox HorizontalAlignment="Right" Width="162" Text="Filter..." TextWrapping="Wrap" Margin="0,44,18,13" />

在viewModel上：

public class BusinessRulesWizardViewModel : INotifyPropertyChanged
    {

public ObservableCollection<string> MachineRulesList
     {
       get { return _machineRulesList; }
       set
          {
            _machineRulesList = value;
             OnPropertyChanged("MachineRulesList");
          }
      }



 public BusinessRulesWizardViewModel(ISystemView systemViewManager, 
       IEventAggregator eventAggregator)
    {
         _machineRulesList = new ObservableCollection<string>();
        _systemViewManager.GetMachines(page, pageSize).ToList().ForEach(
            item => _machineRulesList.Add(item)
         );
    }

Answer 1

使用可以使用ICollectionView接口将Filter属性设置的集合包装为使用TextBox中输入的文本的谓词。这是一个例子：

<ListBox IsSynchronizedWithCurrentItem="True" Visibility="{Binding MachinesPanelVisibility}" 
         ItemsSource="{Binding MachineRulesListView}" 
         SelectedIndex="{Binding ItemSelectionIndex}" />   
<TextBox HorizontalAlignment="Right" Width="162" 
         Text="{Binding FilterText}" 
         TextWrapping="Wrap" Margin="0,44,18,13" />

-

public class BusinessRulesWizardViewModel : INotifyPropertyChanged
{

     public ObservableCollection<string> MachineRulesList
     {
       get { return _machineRulesList; }
       set
          {
            _machineRulesList = value;
             OnPropertyChanged("MachineRulesList");
          }
     }

     public string FilterText
     {
       get { return _filterText; }
       set
          {
            _filterText= value;
             OnPropertyChanged("FilterText");
            MachineRulesListView.Refresh();
          }
     }

     public ICollectionView MachineRulesListView { get; private set; }



    public BusinessRulesWizardViewModel(ISystemView systemViewManager, IEventAggregator eventAggregator)
    {
         _machineRulesList = new ObservableCollection<string>();
        MachineRulesListView = CollectionViewSource.GetDefaultView(_machineRulesList);
        MachineRulesListView.Filter = new Predicate<object>(r => ((string)r).Contains(FilterText));

        _systemViewManager.GetMachines(page, pageSize).ToList().ForEach(
            item => _machineRulesList.Add(item)
         );
    }
}

通过TextBox过滤ListBox中的元素

1 个答案: