C# ListView DragDrop 重新排序不起作用答案

【问题标题】：C# ListView DragDrop Reordering not workingC# ListView DragDrop 重新排序不起作用
【发布时间】：2014-03-02 21:43:07
【问题描述】：

我正在尝试实现ListViewItems 的DragDrop 来重新排序我的列表。

列表不会像我预期的那样重新排序或移动项目。

代码

    private void lstModules_DragDrop(object sender, DragEventArgs e)
    {
        if (e.Data.GetDataPresent(typeof(ListViewItem)))
        {
            lstModules.Alignment = ListViewAlignment.Default;
            if (lstModules.SelectedItems.Count == 0)
                return;

            var p = lstModules.PointToClient(new System.Drawing.Point(e.X, e.Y));

            ListViewItem MovetoNewPosition = lstModules.GetItemAt(p.X, p.Y);

            if (MovetoNewPosition == null) 
                return;

            ListViewItem DropToNewPosition = (e.Data.GetData(typeof(ListView.SelectedListViewItemCollection)) as ListView.SelectedListViewItemCollection)[0];
            ListViewItem CloneToNew = (ListViewItem)DropToNewPosition.Clone();

            int index = MovetoNewPosition.Index;
            lstModules.Items.Remove(DropToNewPosition);
            lstModules.Items.Insert(index, CloneToNew);

            lstModules.Alignment = ListViewAlignment.SnapToGrid;


        }

    }


    private void lstModules_DragEnter(object sender, DragEventArgs e)
    {

        if (e.Data.GetDataPresent(typeof(ListView.SelectedListViewItemCollection)))
        {
            e.Effect = DragDropEffects.Move;
        }

    }


    private void lstModules_ItemDrag(object sender, ItemDragEventArgs e)
    {
        lstModules.DoDragDrop(lstModules.SelectedItems, DragDropEffects.Move);
    }

【问题讨论】：

标签： c# winforms listview drag-and-drop

【解决方案1】：

最近我做了这个代码试试这个。

private ListViewItem tempItem = null;
private void lvTables_MouseDown(object sender, MouseEventArgs e)
{
    if (e.Button == MouseButtons.Left)
    {
        Application.DoEvents();
        tempItem = lvTables.GetItemAt(e.X, e.Y);
        string sData = tempItem.Text + ":" + tempItem.Name;
        DragDropEffects effect = DoDragDrop(sData, DragDropEffects.Move);
        lvTables.Refresh();
    }       
}

private void lvTables_DragEnter(object sender, DragEventArgs e)
{

    if (e.Data.GetDataPresent(DataFormats.StringFormat))
        e.Effect = DragDropEffects.Move;
    else
        e.Effect = DragDropEffects.None;
}

private void lvTables_DragOver(object sender, DragEventArgs e)
{
    if (tempItem != null && lvTables.Items.Contains(tempItem))
    {
        Application.DoEvents();
        int iIndex = -1;
        try
        {
            Point p = lvTables.PointToClient(new Point(e.X, e.Y));
            iIndex = lvTables.GetItemAt(p.X, p.Y).Index;
        }
        catch
        { }
        if (iIndex > -1 && iIndex != tempItem.Index)
        {
            if (lvTables.Items.Contains(tempItem))
                lvTables.Items.Remove(tempItem);
            lvTables.Items.Insert(iIndex, tempItem);
            tempItem.Selected = true;
        }
    }
}

private void lvTables_MouseUp(object sender, MouseEventArgs e)
{
    if (tempItem != null)
    {
        lvTables.SelectedItems.Clear();
        tempItem.Selected = true;
        tempItem = null;
    }
}

【讨论】：