Question

您好，我正在为我的应用程序使用ObjectListView。我尝试制作奇特的拖曳效果，因为原始的蓝色效果不太好。就像我拖动时突出显示第一列。我在普通列表视图中使用了

        private void lvPlaylist_DragOver(object sender, DragEventArgs e)
        {
            Point mLoc = lvPlaylist.PointToClient(Cursor.Position);
            var hitt = lvPlaylist.HitTest(mLoc);
            if (hitt.Item == null) return;

            int idx = hitt.Item.Index;
            if (idx == prevItem) return;

            lvPlaylist.Refresh();
            using (Graphics g = lvPlaylist.CreateGraphics())
            {
                Rectangle rect = lvPlaylist.GetItemRect(idx);
                Pen MyPen = new Pen(Color.OrangeRed, 3);
                g.DrawLine(MyPen, rect.Left, rect.Top, rect.Right, rect.Top);
            }
            prevItem = idx;
        }

但是它在ObjectListView中不起作用。确实可以，但是当我停止拖动但不释放拖动对象时，它向我显示了蓝色的默认拖动效果，而我继续移动时会看到自己的拖动效果。有什么方法可以禁用OLV拖动效果吗？

Answer 1

您的解决方案在所选项目的上方/下方绘制了一条线？

您可以允许在使用之间删除：

lvPlaylist.IsSimpleDropSink = true;
((SimpleDropSink)lvPlaylist.DropSink).CanDropBetween = true;

如果这还不够好，您可以回复ModelCanDrop，例如

//((SimpleDropSink)lvPlaylist.DropSink).ModelCanDrop+= ModelCanDrop;

 private void ModelCanDrop(object sender, ModelDropEventArgs e)
 {
     e.DropSink.Billboard.BackColor = Color.GreenYellow;
     e.DropSink.FeedbackColor = Color.GreenYellow;
     e.InfoMessage = "Hey there";
     e.Handled = true;
     e.Effect = DragDropEffects.Move;
 }

如果您真的讨厌它，甚至可以：

e.DropSink.EnableFeedback = false;

ObjectListView网站提供了有关拖放的深入教程：

http://objectlistview.sourceforge.net/cs/blog4.html#blog-rearrangingtreelistview

如果您想花点时间去做，可以为SimpleDropSink编写自己的子类：

lvPlaylist.IsSimpleDragSource = true;
lvPlaylist.DropSink = new MyDropSink();

private class MyDropSink : SimpleDropSink
{
    public override void DrawFeedback(Graphics g, Rectangle bounds)
    {
        if(DropTargetLocation != DropTargetLocation.None)
            g.DrawString("Heyyy stuffs happening",new Font(FontFamily.GenericMonospace, 10),new SolidBrush(Color.Magenta),bounds.X,bounds.Y );
    }
}

对于您想要的行为，您应该尝试以下操作：

private class MyDropSink : SimpleDropSink
{
    private ObjectListView _olv;

    public MyDropSink(ObjectListView olv)
    {
        _olv = olv;
    }

    public override void DrawFeedback(Graphics g, Rectangle bounds)
    {
        if(DropTargetLocation != DropTargetLocation.None)
        {
            Point mLoc = _olv.PointToClient(Cursor.Position);
            var hitt = _olv.HitTest(mLoc);
            if (hitt.Item == null) return;

            int idx = hitt.Item.Index;
            Rectangle rect = _olv.GetItemRect(idx);
            Pen MyPen = new Pen(Color.OrangeRed, 3);
            g.DrawLine(MyPen, rect.Left, rect.Top, rect.Right, rect.Top);
        }
    }
}

ObjectListView忽略拖动效果

1 个答案: