更改ICollectionView中的项目组

Question

我ICollectionView看起来像

public ICollectionView UsersCollectionView
{
    get
    {
        var view = CollectionViewSource.GetDefaultView(this);
        view.GroupDescriptions.Add(new PropertyGroupDescription("SeriesName"));
        view.SortDescriptions.Add(new SortDescription("CreationDate", ListSortDirection.Ascending));
        view.SortDescriptions.Add(new SortDescription("DocumentTypeId", ListSortDirection.Ascending));
        return view;
    }
}

我想使用拖放来更改项目系列名称和列表视图中的位置,例如,如何做到这一点

--- ScienceFiction
------------> Book1 
------------> Book2
--- History 
------------> Book3 
------------> Book4

如果在ScienceFiction中Iragedd and droped book3,那么输出应该是

--- ScienceFiction
------------> Book1 
------------> Book2
------------> Book3 
--- History 
------------> Book4

我像这样使用xaml代码:

    <UserControl.Resources>
    <Style x:Key="ContainerStyle" TargetType="{x:Type GroupItem}">
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate>
                    <Expander Header="{Binding Name}" IsExpanded="True">
                        <ItemsPresenter />
                    </Expander>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</UserControl.Resources>
<Grid>
    <ListBox x:Name="lbPersonList" Margin="19,17,162,25" AlternationCount="2" ItemsSource="{Binding}">
        <ListBox.GroupStyle>
            <GroupStyle ContainerStyle="{StaticResource ContainerStyle}"/>
        </ListBox.GroupStyle>
        <ListBox.ItemTemplate>
            <DataTemplate>
                <TextBlock Text="{Binding Name}"/>
            </DataTemplate>
        </ListBox.ItemTemplate>
    </ListBox>

</Grid>

Answer 1

抗苗剂，

首先修改ListviewItem的Style。它是包含列表框的每一行（数据模板实例）的容器。这是在行级别管理拖放的好地方（不是行的控件，DataTemplate 中可能有很多控件）。在 Visual Studio 中，选择列表框，右键单击，编辑其他模板/编辑生成的项目容器(ItemContainerStyle)/编辑副本

在创建的 ListBoxItemStyle 中，在 setter 中添加这三个声明：

        <EventSetter Event="ListBoxItem.DragOver" Handler="ListBoxItemDragOver"/>
        <EventSetter Event="ListBoxItem.Drop" Handler="ListBoxItemDrop"/>
        <EventSetter Event="ListBoxItem.PreviewMouseMove" Handler="ListBoxItemPreviewMouseMove"/>

在 ListBox 上将 AllowDrop 属性设置为 true ：

<ListBox x:Name="listboxBooks" AllowDrop="True">

然后在 .xaml.cs 代码中实现处理程序：

    #region DnD management

    private Book sourceBook;
    private void ListBoxItemPreviewMouseMove(object sender, MouseEventArgs e)
    {
        if (e.LeftButton != MouseButtonState.Pressed)
            return;
        var listboxItem = sender as ListBoxItem;
        if (listboxItem == null)
            return;
        sourceBook = listboxItem.DataContext as Book;
        if (sourceBook == null)
            return;
        var data = new DataObject();
        data.SetData(sourceBook);
        // provide some data for DnD in other applications (Word, ...)
        data.SetData(DataFormats.StringFormat, sourceBook.ToString());
        DragDropEffects effect = DragDrop.DoDragDrop(listboxItem, data, DragDropEffects.Move | DragDropEffects.Copy);
    }
    private void ListBoxItemDrop(object sender, DragEventArgs e)
    {
        if (!e.Data.GetDataPresent(typeof(Book)))
            return;
        var listBoxItem = sender as ListBoxItem;
        if (listBoxItem == null)
            return;
        var targetBook = listBoxItem.DataContext as Book;
        if (targetBook != null)
        {
            viewModel.RecategorizeBook(sourceBook, targetBook.Category);
        }
        e.Handled = true;
    }
    private void ListBoxItemDragOver(object sender, DragEventArgs e)
    {
        Debug.WriteLine(e.Effects);
        if (!e.Data.GetDataPresent(typeof(Book)))
        {
            e.Effects = DragDropEffects.None;
            e.Handled = true;
        }
    }
    private void GroupItemDrop(object sender, DragEventArgs e)
    {
        if (!e.Data.GetDataPresent(typeof(Book)))
            return;
        var groupItem = sender as GroupItem;
        if (groupItem == null)
            return;
        dynamic targetGroup = groupItem.DataContext;
        if (targetGroup != null)
        {
            // here I change the category of the book
            // and refresh the view of the collectionViewSource ( see link to project zipped further)
            viewModel.RecategorizeBook(sourceBook, targetGroup.Name as String);
        }
        e.Handled = true;
    }
    #endregion

请注意，我还在处理程序中的组标头上实现了 Drop 管理。因此，需要在 XAML groupstyle 中声明处理程序：

<ListBox.GroupStyle>
    <GroupStyle>
        <GroupStyle.ContainerStyle>
            <Style TargetType="{x:Type GroupItem}">
                <EventSetter Event="GroupItem.Drop" Handler="GroupItemDrop"/>
                <EventSetter Event="GroupItem.PreviewMouseMove" Handler="ListBoxItemPreviewMouseMove"/>

它有效，这里是完整的工作代码：http://1drv.ms/1FhBZwr

祝您获得最好的代码