在 WPF 中向上/向下移动 ListBoxItem [英] Moving ListBoxItem Up/Down in WPF

问题描述

我创建了一个包含文件名的列表框.我想给用户一个选项来使用向上/向下按钮和拖放来向上和向下移动文件名.

I've created a listbox which contain filenames. I want to give user a option to move up and down file name using up/down button and using drag and drop.

任何人都知道如何实现此功能.

Anyone has an idea how to achieve this functionality.

XAML 代码:

<ListBox
    Grid.Column="0"
    Name="listBox1"
    AllowDrop="True"
    Drop="listBox1_Drop"
/>
<StackPanel
    Grid.Column="1"
    HorizontalAlignment="Stretch"
    VerticalAlignment="Center">
    <Button
        Name="moveUp"
        Content="Ç"
        FontFamily="Wingdings 3"
        Margin="3,3,3,3"
        Click="moveUp_Click" />
    <Button
        Name="moveDown"
        FontFamily="Wingdings 3"
        Content="È"
        Margin="3,3,3,3" />
</StackPanel>

推荐答案

如果你不想实现比上移和下移复杂的东西，可以这样处理.如果源看起来像这样

If you don't want to implement something complex than the Move Up and Move Down can be handled like this. If the source looks like this

public ObservableCollection<FileClass> FileNames
{
    get;
    set;
}

private void moveUp_Click(object sender, RoutedEventArgs e)
{
    FileClass selectedfile = listBox1.SelectedItem as FileClass;
    int index = FileNames.IndexOf(selectedfile);
    if (index > 0)
    {
        FileNames.Remove(selectedfile);
        FileNames.Insert(index-1, selectedfile);
        listBox1.SelectedItem = selectedfile;
    }
}

private void moveDown_Click(object sender, RoutedEventArgs e)
{
    FileClass selectedfile = listBox1.SelectedItem as FileClass;
    int index = FileNames.IndexOf(selectedfile);
    if (index < FileNames.Count-1)
    {
        FileNames.Remove(selectedfile);
        FileNames.Insert(index + 1, selectedfile);
        listBox1.SelectedItem = selectedfile;
    }
}

改变
尝试使用此代码通过在 ListBox 中拖放来上下移动项目

CHANGE
Try this code to move items up and down with drag and drop within the ListBox

private void listBox1_Drop(object sender, DragEventArgs e)
{
    ListBox parent = sender as ListBox;
    FileClass data = e.Data.GetData(typeof(FileClass)) as FileClass;
    FileClass objectToPlaceBefore = GetObjectDataFromPoint(parent, e.GetPosition(parent)) as FileClass;
    if (data != null && objectToPlaceBefore != null)
    {
        int index = FileNames.IndexOf(objectToPlaceBefore);
        FileNames.Remove(data);
        FileNames.Insert(index, data);
        listBox1.SelectedItem = data;
    }
}

private void listBox1_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
    ListBox parent = sender as ListBox;
    FileClass data = GetObjectDataFromPoint(parent, e.GetPosition(parent)) as FileClass;
    if (data != null)
    {
        DragDrop.DoDragDrop(parent, data, DragDropEffects.Move);
    }
}

private static object GetObjectDataFromPoint(ListBox source, Point point)
{
    UIElement element = source.InputHitTest(point) as UIElement;
    if (element != null)
    {
        object data = DependencyProperty.UnsetValue;
        while (data == DependencyProperty.UnsetValue)
        {
            data = source.ItemContainerGenerator.ItemFromContainer(element);
            if (data == DependencyProperty.UnsetValue)
                element = VisualTreeHelper.GetParent(element) as UIElement;
            if (element == source)
                return null;
        }
        if (data != DependencyProperty.UnsetValue)
            return data;
    }

    return null;
}

这应该会完成拖放操作.

That should complete the drag'n'drop.

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