导航ListCollectionView时更新SelectedItem

本文关键字：SelectedItem 更新 ListCollectionView 导航 | 更新日期: 2023-09-27 18:19:49

我有一个绑定到Listbox的ListCOollectionView。当我点击它时，我可以选择一个项目。现在，我希望能够转到列表框中的上一个和下一个项目，并同时将其选中。

我的列表框

<ListBox x:Name="Imported_images" SelectedItem="{Binding SelectedImage}" ItemsSource="{Binding SortedImageLibrary}"/>
<Button x:Name="next" Command="{Binding NextImageCommand}" >
<Button x:Name="previous" Command="{Binding PreviousImageCommand}">

ViewModel

private ListCollectionView _sortedImageLibrary;
public ListCollectionView SortedImageLibrary
{
    get
    {
        if (_sortedImageLibrary == null) 
        {
            _sortedImageLibrary = new ListCollectionView(ImageLibrary);
            _sortedImageLibrary.IsLiveSorting = true;
            _sortedImageLibrary.CustomSort = new ImageComparer();                     
         }
        return _sortedImageLibrary; 
    }
    set
    {
        _sortedImageLibrary = value; RaisePropertyChanged();
    }
}
private Image _selectedImage;
public Image SelectedImage   
{
    get { return _selectedImage; }
    set { _selectedImage = value; RaisePropertyChanged("SelectedImage"); }
}
public RelayCommand NextImageCommand { get; set; }
public RelayCommand PreviousImageCommand { get; set; }
public void PreviousImageExecute()
{
    if (SortedImageLibrary.CurrentPosition == 0)
    {
    }
    else
    {
        SortedImageLibrary.MoveCurrentToPrevious();
    }
}
public void NextImageExecute()
{
    if (SortedImageLibrary.CurrentPosition == SortedImageLibrary.Count - 1)
    {
    }
    else
    {
        SortedImageLibrary.MoveCurrentToNext();
    }
}

我可以转到ListCollectionView中的下一个和上一个项目，但SelectedImage不会更新。在ListCollectionView中导航时，如何更新所选图像？

导航ListCollectionView时更新SelectedItem

我认为您只需要在导航上设置SelectedImage属性的实例。PropertyChangedEvent应触发WPF端的更新。

我不确定，但我想它应该看起来像这样：

public void PreviousImageExecute()
{
    if (SortedImageLibrary.CurrentPosition == 0)
    {
    }
    else
    {
        SortedImageLibrary.MoveCurrentToPrevious();
    }
    SelectedImage = SortedImageLibrary.CurrentItem as Image;
}
public void NextImageExecute()
{
    if (SortedImageLibrary.CurrentPosition == SortedImageLibrary.Count - 1)
    {
    }
    else
    {
        SortedImageLibrary.MoveCurrentToNext();
    }
    SelectedImage = SortedImageLibrary.CurrentItem as Image;
}

导航后，应将CurrentItem分配给SelectedImage属性。当然，你需要在分配任务之前评估你的导航方法是否返回true。

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