Question

我创建了自己的日历。我日历中的每一天都是一个itemsControl，它包含一个文本块和一个列表框，它应该按日期保存项目。

如何使用ItemsControl中绑定文本块中的字符串值过滤集合？文本块与日期类的日期属性绑定。

视图模型

 public ObservableCollection<Day> Days { get; set; }

 public ObservableCollection<Scene> SceneList;

 private ListCollectionView _sceneCollection;
 public ListCollectionView SceneCollection
 {
     get
     {
         if (_sceneCollection == null) //important for loading the app
         {
             _sceneCollection = new ListCollectionView(this.SceneList);
             _sceneCollection.IsLiveFiltering = true;
             _sceneCollection.Filter = o =>
             {
                 var Scene = o as Scene;
                 return Scene != null && Scene.Date == ////string of binded TextBlock//;
             };
         }
         return _sceneCollection;
     }
     set
     {
         _sceneCollection = value; RaisePropertyChanged();
     }
 }

模型

public class Day : INotifyPropertyChanged
{
     private DateTime date;
     public DateTime Date
     {
        get { return date; }
        set
        {
            date = value;
            if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs("Date"));
        }
     }
 }

的Xaml

<ItemsControl ItemsSource="{Binding Days}">         
        <ItemsControl.ItemsPanel>
            <ItemsPanelTemplate>
                <UniformGrid Rows="6" Columns="7">                     
                </UniformGrid>                  
            </ItemsPanelTemplate>
        </ItemsControl.ItemsPanel>

        <ItemsControl.ItemTemplate>
            <DataTemplate>
                <StackPanel>
                    <TextBlock Text="{Binding Date , Converter={StaticResource DateConverter}, ConverterParameter=DAY}"/>                       
                    <ListBox  ItemsSource="{Binding SceneCollection}" dd:DragDrop.IsDragSource="True"
     dd:DragDrop.IsDropTarget="True" Height="100">
                    <ListBox.ItemTemplate>
                        <DataTemplate>
                            <StackPanel>
                                <TextBlock>
                                     <Run Text="{Binding Path=SceneNumber}"/>
                                     <Run Text="{Binding Path=SlugLine}"/>
                                </TextBlock>
                            </StackPanel>
                        </DataTemplate>
                    </ListBox.ItemTemplate>
                   </ListBox>
                </StackPanel>
            </DataTemplate>
        </ItemsControl.ItemTemplate>
    </ItemsControl>

Answer 1

首先，ListBox的ItemsSource绑定将不起作用，因为它的DataContext是Day对象，而SceneCollection属性不存在，但在ViewModel中。

此外，您不应在ViewModel中过滤您的集合，因为所有项目都将绑定到它，并且它们需要不同的过滤器。

在你的情况下，如果你想在保持底层集合完整的同时使用过滤器和集合视图，我只需在你的'Day'类中添加一个'ICollectionView'属性，并为每一天分配一个SceneCollection的过滤视图。

型号：

public class Day : INotifyPropertyChanged
{
    private DateTime date;
    public DateTime Date
    {
        get { return date; }
        set
        {
            date = value;
            if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs("Date"));
        }
    }

    private ICollectionView scenes;
    public ICollectionView Scenes
    {
        get { return scenes; }
        set
        {
            scenes = value;
            if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs("Scenes"));
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;
}

ViewModel（示例），在您的Days集合初始化中：

private IEnumerable<Day> CreateDaysData()
{
    var maxDays = DateTime.DaysInMonth(DateTime.Now.Year, DateTime.Now.Month);

    for (int d = 1; d <= maxDays; d++)
    {
        var day = new Day
        {
            Date = new DateTime(DateTime.Now.Year, DateTime.Now.Month, d)
        };

        var viewSource = new CollectionViewSource
        {
            Source = ScenesCollection
        };

        viewSource.Filter += new FilterEventHandler((o, e) =>
        {
            e.Accepted = (e.Item as Scene).Date == day.Date;
        });

        day.Scenes = viewSource.View;

        yield return day;
    }
}

最后，您的XAML最终会像这样：

<ItemsControl ItemsSource="{Binding Days}">         
    <ItemsControl.ItemsPanel>
        <ItemsPanelTemplate>
            <UniformGrid Rows="6" Columns="7">                     
            </UniformGrid>                  
        </ItemsPanelTemplate>
    </ItemsControl.ItemsPanel>

    <ItemsControl.ItemTemplate>
        <DataTemplate>
            <StackPanel>
                <TextBlock Text="{Binding Date , Converter={StaticResource DateConverter}, ConverterParameter=DAY}"/>               
                <!-- The ListBox's ItemsSource is bound to the ICollectionView of your Day class -->        
                <ListBox  ItemsSource="{Binding Scenes}" dd:DragDrop.IsDragSource="True"
 dd:DragDrop.IsDropTarget="True" Height="100">
                <ListBox.ItemTemplate>
                    <DataTemplate>
                        <StackPanel>
                            <TextBlock>
                                 <Run Text="{Binding Path=SceneNumber}"/>
                                 <Run Text="{Binding Path=SlugLine}"/>
                            </TextBlock>
                        </StackPanel>
                    </DataTemplate>
                </ListBox.ItemTemplate>
               </ListBox>
            </StackPanel>
        </DataTemplate>
    </ItemsControl.ItemTemplate>
</ItemsControl>

使用ItemsControl中的TextBlock值在ListBox中过滤集合

1 个答案: