我试图在拖放操作生效时更改鼠标光标,但是根本看起来似乎不起作用.我已经改变了所有必要的值,并且在不同的事件期间鼠标光标,但是没有用.

下面的代码有没有什么东西会阻止正确的行为？基本上,显示的光标总是默认的拖放光标(移动,复制等)…请注意,我还启用了TreeView中的HotTracking来启用GiveFeedback,并触发/击中断点.

[编辑] – 感谢汉斯解决方案.基本上,DoDragDrop调用必须通过使用其FQN来定位到您想要的控件.如果您的源代码控件是触发ItemDrag事件的,那么您必须明确指定它.见下面更新的代码.

#region Drag and Drop Methods and Event Handlers
        /// <summary>
        /// Performs the necessary actions when the user drags and drops a node around the treeview.
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void tv_Terms_DragDrop(object sender,DragEventArgs e)
        {
            // Retrieve the client coordinates of the drop location.
            Point targetPoint = this.tv_Terms.PointToClient(new Point(e.X,e.Y));

            // Retrieve the node at the drop location.
            TreeNode targetNode = this.tv_Terms.GetNodeAt(targetPoint);

            // confirm that the target node isn't null
            // (for example if you drag outside the control)
            if (targetNode != null)
            {

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

                //PERFORM DB OPERATIONS HERE>>

                // Expand the node at the location 
                // to show the dropped node.
                targetNode.Expand();
            }
        }

        /// <summary>
        /// Adds the necessary effect when dragging.
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void tv_Terms_ItemDrag(object sender,ItemDragEventArgs e)
        {
            this.tv_Terms.DoDragDrop(e.Item,DragDropEffects.Move);
        }

        /// <summary>
        /// Adds the necessary effect when dragging.
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void tv_Terms_DragEnter(object sender,DragEventArgs e)
        {
            if(e.Data.GetDataPresent(typeof(TreeNode)) == true)
                e.Effect = DragDropEffects.Move;
        }

        /// <summary>
        /// Selects the appropriate node when the user is dragging an item.
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void tv_Terms_DragOver(object sender,DragEventArgs e)
        {
            //THIS METHOD AUTO-SCROLLS THE TREEVIEW IF YOU REACH THE EDGES...
            this.tv_Terms.Scroll();
            TreeNode node = this.tv_Terms.GetNodeAt(this.tv_Terms.PointToClient(new Point(e.X,e.Y)));
            if (node != null)
            {
                NodeInfo info = node.Tag as NodeInfo;

                if (!info.IsContainer)
                    node = node.Parent;

                this.tv_Terms.SelectedNode = node;
            }
        }

        private void tv_Terms_GiveFeedback(object sender,GiveFeedbackEventArgs e)
        {
            //I DON'T CARE WHAT TYPE OF DRAG IT IS,ALWAYS USE THE CUSTOM CURSOR.
            e.UseDefaultCursors = false;
            Cursor.Current = lastcursor;                
        }

        //I SET/CACHE THE MOUSE CURSOR HERE
        private void tv_Terms_MouseDown(object sender,MouseEventArgs e)
        {
            TreeNode node = this.tv_Terms.GetNodeAt(e.X,e.Y);
            if (node != null)
            {
                //THIS METHOD CREATES THE CUSTOM CURSOR.
                Bitmap curs = Helpers.CreateNodeCursorIcon(this.imageList1.Images[node.ImageIndex],node.Text);
                this.lastcursor = new Cursor(curs.GetHicon());
                //I CONFIRM THE PROPER CURSOR BY PLACING THE IMAGE IN A P.B.
                this.pictureBox1.Image = curs;
                Cursor.Current = lastcursor;
            }

        }

        #endregion