Winform开发遇到的问题之生成拖拽控件

1.代码块：

        //记录位置
        Point po = Point.Empty;
        //生成的控件
        Label lbl = null;
        Label txt = null;

        // 接口方法
        RegionlStaffQueryManager rsqm = new RegionlStaffQueryManager();//获取生成控件的Count
        List<AreaParameterBusiness> list = new List<AreaParameterBusiness>();//实体

        //默认加载Load
        private void newAreaPicQuery_Load(object sender, EventArgs e)
        {
            CreateControls();
            this.gbfill.AllowDrop = true;
        }

        /// <summary>
        /// 区域名称初始化
        /// </summary>
        private void CreateControls()
        {
            int x = 10;
            int y = 20;
            list = rsqm.AreaConfigInfo();
            for (int i = 0; i < list.Count; i++)
            {
                string lbltext = list[i].AreaName;
                string lblname = "lbl" + list[i].SystemID;
                lbl = new Label();
                lbl.Left = x;
                lbl.Top = y;
                lbl.Font = new Font("楷书", 14, FontStyle.Bold);
                lbl.Name = lblname;
                lbl.Text = lbltext;
                lbl.ContextMenuStrip = menu;
                lbl.TextAlign = System.Drawing.ContentAlignment.MiddleCenter;
                lbl.BorderStyle = System.Windows.Forms.BorderStyle.FixedSingle;
                lbl.DoubleClick += lbl_DoubleClick;
                x += lbl.Width + 5;
                if (lbl.Width > gbleft.Width - x)
                {
                    x = 10;
                    y += lbl.Height + 10;
                }
                this.gbleft.Controls.Add(lbl);
            }
        }

        /// <summary>
        ///  双击产生区域文本
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        void lbl_DoubleClick(object sender, EventArgs e)
        {
            string checkname = ((Label)sender).Name;
            string checktext = null;
            string TextName = ((Label)sender).Text;
            Control con = ExtensionClass.FindControl(gbfill, checkname);
            if (con == null)
            {
                list = rsqm.AreaConfigInfo();
                for (int i = 0; i < list.Count; i++)
                {
                    if (TextName.Equals(list[i].AreaName))
                    {
                        checktext = "区域名称：" + list[i].AreaName + "\r\n" + "区域人数：" + list[i].TheTotal;
                    }
                }
                txt = new Label();
                txt.AutoSize = false;
                txt.BackColor = Color.Transparent;
                txt.ForeColor = Color.Aqua;
                txt.Name = checkname;
                txt.Text = checktext;
                //窗体重绘，具有边框颜色
                //txt.Paint += txt_Paint; 
                txt.TextAlign = System.Drawing.ContentAlignment.MiddleCenter;
                //读取配置文件
                txt.Location = new Point(5, 10);
                txt.Height = Convert.ToInt32(AppConfig.height);
                txt.Width = Convert.ToInt32(AppConfig.width);
                txt.AllowDrop = true;
                txt.MouseUp += txt_MouseUp;
                txt.MouseDown += txt_MouseDown;
                this.gbfill.Controls.Add(txt);
            }
            else
            {
                MessageBox.Show("已经存在");
            }

        }
        //鼠标按下
        private void txt_MouseDown(object sender, MouseEventArgs e)
        {
            txt = (Label)sender;
        }
        //鼠标释放
        private void txt_MouseUp(object sender, MouseEventArgs e)
        {
            txt.Location = getPointToForm(new Point(e.Location.X - gbfill.Location.X, e.Location.Y));
            txt.DoDragDrop(txt, DragDropEffects.Move);
        }
        private Point getPointToForm(Point p)
        {
            return this.PointToClient(txt.PointToScreen(p));
        }

2.效果图：