如何拖&在同一个ListView中放置项目？ [英] How to drag & drop items in the same ListView?

问题描述

是一个ListView，显示文件和文件夹，我已经写了代码复制/移动/重命名/显示属性...等等，我只需要一个最后一件事。如何在Windows资源管理器中拖放相同的ListView，我有移动和复制功能，我只需要获取某些文件夹中丢弃的项目，或以其他方式，我需要获取这两个参数来调用复制功能

Consider this is a ListView that shows files and folders, I have already wrote code for copy/move/rename/show properties ...etc and I just need one more last thing. how to drag and drop in the same ListView like in Windows Explorer, I have move and copy functions, and I just need to get the items which user drops in some folder or in other way I need to get these two parameters to call copy function

void copy(ListViewItem [] droppedItems, string destination path)
{
 // Copy target to destination
}

推荐答案

p>首先将列表视图的AllowDrop属性设置为true。实现ItemDrag事件以检测拖动的开始。我将使用一个私有变量来确保D + D只能在控件内部工作：

Start by setting the list view's AllowDrop property to true. Implementing the ItemDrag event to detect the start of a drag. I'll use a private variable to ensure that D+D only works inside of the control:

    bool privateDrag;

    private void listView1_ItemDrag(object sender, ItemDragEventArgs e) {
        privateDrag = true;
        DoDragDrop(e.Item, DragDropEffects.Copy);
        privateDrag = false;
    }

接下来，您将需要DragEnter事件，它将立即触发： p>

Next you'll need the DragEnter event, it will fire immediately:

    private void listView1_DragEnter(object sender, DragEventArgs e) {
        if (privateDrag) e.Effect = e.AllowedEffect;
    }

接下来，您将希望选择用户可以删除的项目。这需要DragOver事件并检查哪个项目被悬停。您需要将代表文件夹的项目与常规文件项区分开。一种方法可以通过使用ListViewItem.Tag属性来实现。您可以将其设置为文件夹的路径。使此代码工作：

Next you'll want to be selective about what item the user can drop on. That requires the DragOver event and checking which item is being hovered. You'll need to distinguish items that represent a folder from regular 'file' items. One way you can do so is by using the ListViewItem.Tag property. You could for example set it to the path of the folder. Making this code work:

    private void listView1_DragOver(object sender, DragEventArgs e) {
        var pos = listView1.PointToClient(new Point(e.X, e.Y));
        var hit = listView1.HitTest(pos);
        if (hit.Item != null && hit.Item.Tag != null) {
            var dragItem = (ListViewItem)e.Data.GetData(typeof(ListViewItem));
            copy(dragItem, (string)hit.Item.Tag);
        }
    }

如果您要支持拖动多个项目，拖动对象ListView.SelectedIndices属性。

If you want to support dragging multiple items then make your drag object the ListView.SelectedIndices property.

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