c# - 如何在拖动时突出显示目标节点

Question

我有一个 TreeView 并试图将节点移动到父节点(拖放)，

有什么方法可以让目标节点在鼠标悬停时显示背景颜色(左键仍然按住并拖动项目)？

[更新]为什么下面的代码不起作用？？

    private TreeNode nodeOver=null;
    private void treeView_DragOver(object sender, DragEventArgs e)
    {
       Point p = treeView.PointToClient(new Point(e.X, e.Y));
       nodeOver = treeView.GetNodeAt(p.X, p.Y);
        nodeOver.BackColor = Color.Aquamarine;
    }
    private void treeView_DragLeave(object sender, EventArgs e)
    {
        nodeOver.BackColor = Color.White;
    }

Answer 1

你可以尝试这样的事情:

    private void treeView_DragOver(object sender, DragEventArgs e)
    {
        ClearBackground(treeView.Nodes);
        Point p = treeView.PointToClient(new Point(e.X, e.Y));
        TreeNode node = treeView.GetNodeAt(p.X, p.Y);
        node.BackColor = Color.Aquamarine;
    }

    private void ClearBackground(TreeNodeCollection nodes)
    {
        foreach (TreeNode node in nodes)
        {
            node.BackColor = Color.White;
            ClearBackground(node.Nodes);
        }
    }

编辑

这是一个不会引起闪烁的改进版本:

    private void treeView_DragOver(object sender, DragEventArgs e)
    {
        Point p = treeView.PointToClient(new Point(e.X, e.Y));
        TreeNode node = treeView.GetNodeAt(p.X, p.Y);
        if (node.PrevVisibleNode != null)
        {
            node.PrevVisibleNode.BackColor = Color.White;
        }
        if (node.NextVisibleNode != null)
        {
            node.NextVisibleNode.BackColor = Color.White;
        }
        node.BackColor = Color.Aquamarine;
    }