更改列表视图仅在XAML中排序属性/方向

Question

我有一个简单的ListView，想要按数字或字母顺序，升序或降序对内容进行排序。选择来自下拉框。我知道我可以使用CollectionViewSource来实现排序，但是如何动态改变SortDescription或方向？

更新

好的，所以我设置了我的CVS，viewModel就是ListView当前绑定的内容。我要求PropertyName绑定到当前选定的组合框项的属性PropertyName。组合框绑定到一个自定义列表，该列表显示我要对其进行排序的属性名称。

它抱怨我尝试使用的PropertyName：

  

无法在类型的'PropertyName'属性上设置'绑定'   'SortDescription'。 '绑定'只能在DependencyProperty上设置   DependencyObject。

    <CollectionViewSource Source="{StaticResource viewModel.ListValues}" x:Key="cvs">
        <CollectionViewSource.SortDescriptions>
            <scm:SortDescription PropertyName="{Binding Path=SortPropertyName, Source=comboSort}"/>
        </CollectionViewSource.SortDescriptions>
    </CollectionViewSource>

    <ListView ItemsSource="{Binding Source={StaticResource cvs}}"  />

Answer 1

你可以在viewmodel

中使用代码

// in your view model
private void ChangeSorting () {
  var collView = CollectionViewSource.GetDefaultView(ListValues);
  collView.SortDescriptions.Clear();
  // do this one
  collView.SortDescriptions.Add(new SortDescription("YourPropertyName", ListSortDirection.Ascending));
  // or this one
  collView.SortDescriptions.Add(new SortDescription("YourOtherPropertyName", ListSortDirection.Descending));
  collView.Refresh();
}

public ICollectionView ListValuesCollectionViewSource
{
  get {
    return collView;
  }
}

<ListView ItemsSource="{Binding viewModel.ListValuesCollectionViewSource}"  />

修改

这是您的视图模型的一个小例子

<ComboBox ItemsSource="{Binding viewmodel.YourDataForComboboxCollection, Mode=OneWay}"
          SelectedItem="{Binding viewmodel.SelectedCombobox}" />

一个小视图模型

using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Windows;
using System.Windows.Data;

namespace YourNameSpace
{
  public class ViewModel : INotifyPropertyChanged
  {
    public static readonly DependencyProperty SelectedComboboxProperty =
      DependencyProperty.Register("SelectedCombobox", typeof(YourDataForCombobox), typeof(ViewModel), new PropertyMetadata(default(YourDataForCombobox), new PropertyChangedCallback(SelectedComboboxCallback)));

    private static void SelectedComboboxCallback(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e) {
      var vm = sender as ViewModel;
      if (vm != null && e.NewValue != null && e.NewValue != e.OldValue) {
        vm.ChangeSorting(e.NewValue);
      }
    }

    public ViewModel() {
      this.YourDataForComboboxCollection = new ObservableCollection<YourDataForCombobox>();
    }

    private void ChangeSorting(YourDataForCombobox newValue) {
      this.yourCollectionView.SortDescriptions.Clear();
      this.yourCollectionView.SortDescriptions.Add(new SortDescription(newValue.PropertyName, newValue.Sorting));
      this.yourCollectionView.Refresh();
    }

    private IObservableCollection yourDataForComboboxCollection;

    public IObservableCollection YourDataForComboboxCollection {
      get { return this.yourDataForComboboxCollection; }
      set {
        this.yourDataForComboboxCollection = value;
        this.RaisePropertyChanged("YourDataForComboboxCollection");
      }
    }

    public YourDataForCombobox SelectedCombobox {
      get { return (YourDataForCombobox)GetValue(SelectedComboboxProperty); }
      set { SetValue(SelectedComboboxProperty, value); }
    }

    private IObservableCollection yourCollection;
    private ICollectionView yourCollectionView;

    public ICollectionView YourCollectionView {
      get { return this.GetCollectionView(); }
    }

    private ICollectionView GetCollectionView() {
      if (this.yourCollection == null) {
        this.yourCollection = new ObservableCollection<YourDataForCollection>();
        this.yourCollectionView = CollectionViewSource.GetDefaultView(this.yourCollection);
        // initial sorting
        this.ChangeSorting(null);
      }
      return this.yourCollectionView;
    }

    private void RaisePropertyChanged(string property) {
      var eh = this.PropertyChanged;
      if (eh != null) {
        eh(this, new PropertyChangedEventArgs(property));
      }
    }

    public event PropertyChangedEventHandler PropertyChanged;
  }
}

希望这会有所帮助

Answer 2

您还可以将其置于行为中，添加另一个要绑定的属性以动态设置排序描述方向，但此解决方案仅适用于按一个属性排序。它当然可以扩展到更多的工作。

XAML：

    <CollectionViewSource x:Key="GroupedMeetingItems" Source="{Binding Items}" util:CollectionViewSourceBehavior.IsAscending="{Binding IsItemsAscending}">
        <CollectionViewSource.GroupDescriptions>
            <PropertyGroupDescription PropertyName="StartDateTime" Converter="{StaticResource DateTimeToDisplayDateConverter}" />
        </CollectionViewSource.GroupDescriptions>
        <CollectionViewSource.SortDescriptions>
            <scm:SortDescription PropertyName="StartDateTime" Direction="Descending"/>
        </CollectionViewSource.SortDescriptions>
    </CollectionViewSource> 

行为：

public static class CollectionViewSourceBehavior
{
    public static readonly DependencyProperty IsAscendingProperty =
        DependencyProperty.RegisterAttached(
            "IsAscending",
            typeof(bool),
            typeof(CollectionViewSourceBehavior),
            new UIPropertyMetadata(false, OnIsAscendingChanged));

    public static object GetIsAscending(FrameworkElement element)
    {
        return element.GetValue(IsAscendingProperty);
    }

    public static void SetIsAscending(FrameworkElement element, object value)
    {
        element.SetValue(IsAscendingProperty, value);
    }

    public static void OnIsAscendingChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e)
    {
        var collectionViewSource = dependencyObject as CollectionViewSource;
        if (collectionViewSource == null)
        {
            return;
        }

        var isAscending = e.NewValue as bool? == true;
        var newSortDescription = new SortDescription
            {
                Direction = isAscending ? ListSortDirection.Ascending : ListSortDirection.Descending,
                PropertyName = collectionViewSource.SortDescriptions.FirstOrDefault().PropertyName
            };
        collectionViewSource.SortDescriptions.Clear();
        collectionViewSource.SortDescriptions.Add(newSortDescription);
    }
}