从拖动列表视图WPF多个项目 [英] Drag multiple items from WPF listview

问题描述

我有一个从目录显示文件列表视图。结果
用户可以在ListView的每个项目拖到一个文件夹/桌面和相关文件被复制那里。结果
这工作得很好。是 - 我想对多个物品─使用户可以选择多个listviewitems并拖动这样做，并复制它们在一起的问题。
ListView控件设置为SelectedMode = MULTIPLE-，但它不会复制所有选定的项目。
这里是我的code：

I have a listview that displays files from a directory.
The user can drag each item in the listview to a folder/ the desktop and the associated file is copied there.
This works fine. The problem is- I want to do so for multiple items- so the user can select multiple listviewitems and drag and copy them together. The ListView is set to SelectedMode=Multiple- but it doesn't copy all of the selected items. Here's my code:

    private void FileView_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
    {
        this.start = e.GetPosition(null);
    }

    private void FileView_MouseMove(object sender, MouseEventArgs e)
    {
        Point mpos = e.GetPosition(null);
        Vector diff = this.start - mpos;

        if (e.LeftButton == MouseButtonState.Pressed &&
            Math.Abs(diff.X) > SystemParameters.MinimumHorizontalDragDistance &&
            Math.Abs(diff.Y) > SystemParameters.MinimumVerticalDragDistance)
        {
            if (this.FileView.SelectedItems.Count == 0)
            {
                return;
            }

            // right about here you get the file urls of the selected items.  
            // should be quite easy, if not, ask.  
            string[] files = new String[1];
            files[0] = "C:\\Users\\MyName\\Music\\My playlist\\" + FileView.SelectedValue.ToString();
            string dataFormat = DataFormats.FileDrop;
            DataObject dataObject = new DataObject(dataFormat, files);
            DragDrop.DoDragDrop(this.FileView, dataObject, DragDropEffects.Copy);
        } 
    }

谢谢！

推荐答案

这里的问题是，你正在使用的SelectedValue为多选，让你获得一个文件。你想要的是像这样的东西更多：

The problem here is that you are using SelectedValue for a multiselect, so you get one file. What you want is something more like this:

private void FileView_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
    this.start = e.GetPosition(null);
}

private void FileView_MouseMove(object sender, MouseEventArgs e)
{
    Point mpos = e.GetPosition(null);
    Vector diff = this.start - mpos;

    if (e.LeftButton == MouseButtonState.Pressed &&
        Math.Abs(diff.X) > SystemParameters.MinimumHorizontalDragDistance &&
        Math.Abs(diff.Y) > SystemParameters.MinimumVerticalDragDistance)
    {
        if (this.FileView.SelectedItems.Count == 0)
            return;

        // right about here you get the file urls of the selected items.  
        // should be quite easy, if not, ask.  
        string[] files = new String[FileView.SelectedItems.Count];
        int ix = 0;
        foreach (object nextSel in FileView.SelectedItems)
        {
            files[ix] = "C:\\Users\\MyName\\Music\\My playlist\\" + nextSel.ToString();
            ++ix;
        }
        string dataFormat = DataFormats.FileDrop;
        DataObject dataObject = new DataObject(dataFormat, files);
        DragDrop.DoDragDrop(this.FileView, dataObject, DragDropEffects.Copy);
    } 
}

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