TableLayoutControl DragNDrop问题

Question

我在表单上有一个Treeview和列表框控件。 使用以下方法处理从TreeView到ListBox的项目：

void ListBoxDrop(Dictionary<string, string> datasource, DragEventArgs e)
        {
            // Retrieve the client coordinates of the drop location.
            Point targetPoint = this.PointToClient(new Point(e.X, e.Y));

            // Retrieve the listBox at the drop location. (This is where it sees a TableLayoutControl)       
            object controlAtPoint = this.GetChildAtPoint(targetPoint);
            if (!(controlAtPoint is ListBox))
                return;

            ListBox targetListbox = this.GetChildAtPoint(targetPoint) as ListBox;

            // Retrieve the node that was dragged.
            TreeNode draggedNode = (TreeNode)e.Data.GetData(typeof(TreeNode));

            // Only add the item if it doesnt already exist in the list.             
            if (!datasource.ContainsKey(draggedNode.Tag.ToString()))
            {
                datasource.Add(draggedNode.Tag.ToString(), draggedNode.Text);
            }
        }

问题是当我将TableLayoutPanel从容器工具箱拖到我的表单上，然后将ListBox移动到TableLayoutPanel单元格之一时。 从TreeView拖动到列表框时现在发生的是this.GetChildAtPoint（targetPoint）返回TableLayoutPanel控件引用而不是ListBox控件。

有没有办法让这个.GetChildAtPoint返回列表框而不是它的容器控件？

Dankie

Answer 1

您必须将this更改为TableLayoutPanel控件：

Point targetPoint = tlp.PointToClient(new Point(e.X, e.Y));
object controlAtPoint = tlp.GetChildAtPoint(targetPoint);
if (!(controlAtPoint is ListBox))
  return;
ListBox targetListbox = tlp.GetChildAtPoint(targetPoint) as ListBox;

Answer 2

GetChildAtPoint（）没有按照你的希望做到。它不会遍历嵌套控件并找到最深的嵌套控件。它只会查看 this 的子项，即表单。因此，恢复TableLayoutPanel是预期的结果。

所以可以自己迭代，像这样：

    Control box = this;
    do {
        var targetPoint = box.PointToClient(new Point(e.X, e.Y));
        box = box.GetChildAtPoint(targetPoint);
        if (box == null) return;
    } while (!(box is ListBox));