Dev TreeList拖拽詳解（內部節點拖拽）

1、設置屬性OptionsBehavior

Editable = False,

DragNodes = True

設置完之後，就可以進行基礎的節點拖拽了

2、增加拖拽邏輯

主要用到三個函數：

BeforeDragNode()（拖拽前判斷選中的節點是否可被拖拽)；

DragDrop()（拖拽時判斷是否可以拖拽到目標節點的子節點或兄弟節點）；

AfterFocusNode()（拖拽成功後的事件）

        #region treelist拖拽操作

        private void treeList1_BeforeDragNode(object sender, BeforeDragNodeEventArgs e)
        {
            TreeListNode moveNode = treeList1.FocusedNode;
            string test = moveNode.GetValue(0).ToString();

            //節點"測試1"不能被拖拽
            if (moveNode.GetValue(0).ToString() == "測試1")
            {
                e.CanDrag = false;
            }
        }

        private void treeList1_DragDrop(object sender, DragEventArgs e)
        {
            System.Drawing.Point p = new System.Drawing.Point(MousePosition.X, MousePosition.Y);
            System.Drawing.Point npt = this.treeList1.PointToClient(p);
            TreeListNode selectNode = this.treeList1.CalcHitInfo(npt).Node; 
            //不能拖拽成爲節點“測試2”的子節點
            if (selectNode.GetValue(0).ToString() == "測試2")
            {
                Rectangle focuseNodeBounds = treeList1.ViewInfo.RowsInfo[treeList1.FocusedNode].Bounds;//選中節點
                Rectangle targetNodeBounds = treeList1.ViewInfo.RowsInfo[selectNode].Bounds;
                int offset = targetNodeBounds.Height / 3;

                if (!(npt.Y >= targetNodeBounds.Top && npt.Y <= targetNodeBounds.Top + offset))
                {
                    e.Effect = DragDropEffects.None;
                }

                //如果選中節點在目標節點下方
                if (focuseNodeBounds.Top > targetNodeBounds.Top)
                {
                    if (!(pt.Y >= targetNodeBounds.Top && pt.Y <= targetNodeBounds.Top + offset))
                    {
                        //不能移動到圖層節點的子節點
                        e.Effect = DragDropEffects.None;
                    }
                }
                else
                {
                    if (!(pt.Y <= targetNodeBounds.Bottom && pt.Y >= targetNodeBounds.Bottom - offset))
                    {
                        //不能移動到圖層節點的子節點
                        e.Effect = DragDropEffects.None;
                    }
                }
            }
        }

        private void treeList1_AfterDragNode(object sender, NodeEventArgs e)
        {
            TreeListNode moveNode = treeList1.FocusedNode.ParentNode;//拖拽後的父節點
            

            //拖拽後事件
        }

        #endregion