实现方法，在datagridview的mousedown事件中开始 托放。
然后在treeview 的 DragEnter 中接收托放。
最后在treeview的 DragDrop 中处理托放结果。
注：treeview的allowdrop属性要设置为 true。
：
 1private void dataGridView1_MouseDown(object sender, MouseEventArgs e)
 2        {
 3            if (e.Button == MouseButtons.Right)
 4            {
 5                DataGridView.HitTestInfo info = dataGridView1.HitTest(e.X, e.Y);
 6               
 7                if (info.RowIndex >= 0)
 8                {
 9                    DataGridViewRow dr = (DataGridViewRow)
10                           dataGridView1.Rows[info.RowIndex];
11                    if (dr != null)
12                        dataGridView1.DoDragDrop(dr, DragDropEffects.Copy);
13                }
14            }
15        }
16
17        private void treeView1_DragEnter(object sender, DragEventArgs e)
18        {
19            e.Effect = DragDropEffects.Copy;
20        }
21
22        private void treeView1_DragDrop(object sender, DragEventArgs e)
23        {
24            if (e.Data.GetDataPresent(typeof(DataGridViewRow)))
25            {               
26                Point p = treeView1.PointToClient(new Point(e.X, e.Y));
27                TreeViewHitTestInfo index = treeView1.HitTest(p);
28
29                if (index.Node != null)
30                {
31
32                    DataGridViewRow drv = (DataGridViewRow)e.Data.GetData(typeof(DataGridViewRow));
33                    index.Node.Text = "Drop: " + drv.Cells[0].ToString();
34            
35                }
36            }
37        }