前些日子因為工作需要想了解有關於在C#下實現執行時滑鼠移動控制元件的方法,Google了一下還真找到了一個帖子,粗略看去程式碼還真不少,感覺有點複雜的樣子,因為當時手頭上還有點別的事情,沒來得及細看,就把帖子轉到了自己的blog裡面收藏。週末晚上沒事,抽時間看了一下程式,發現只能以Form為容器進行操作(因為使用了Form的一些屬性來確定控制元件位置),不完全符合自己的需要,而且作者的實現程式碼似乎多了一點,就自己琢磨著怎麼給精簡一下,後來竟然把幾乎把大部分程式碼給刪掉了,實現方式也有不同,也可以在Form之外的其它容器內進行元件執行時拖動。為了程式可讀性,暫未把改變控制元件大小的程式碼加進來,但基本原理和移動控制元件位置也相差不遠,稍晚一點再新增進來。

/// <summary>
    /// 使視窗的中的指定控制元件支援執行時移動
    /// TODO:執行時縮放
    /// </summary>
    public class ControlMoveResize
    {
        #region 私有成員
        bool IsMoving = false;
        Point pCtrlLastCoordinate = new Point(0,0);
        Point pCursorOffset = new Point(0, 0);
        Point pCursorLastCoordinate = new Point(0, 0);
        private Control ctrl = null;
        private ScrollableControl Containe = null;
        #endregion
        #region 私有方法
        /// <summary>
        /// 在滑鼠左鍵按下的狀態記錄滑鼠當前的位置,以及被移動元件的當前位置
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void MouseDown(object sender, MouseEventArgs e)
        {
            if (Containe == null)
            {
                return;
            }
            if (e.Button == MouseButtons.Left)
            {
                IsMoving = true;
                pCtrlLastCoordinate.X = ctrl.Left;
                pCtrlLastCoordinate.Y = ctrl.Top;
                pCursorLastCoordinate.X = Cursor.Position.X;
                pCursorLastCoordinate.Y = Cursor.Position.Y;
            }
        }
        private void MouseMove(object sender, MouseEventArgs e)
        {
            if (Containe == null)
            {
                return;
            }
               
            if (e.Button == MouseButtons.Left)
            {
                if (this.IsMoving)
                {
                    Point pCursor = new Point(Cursor.Position.X, Cursor.Position.Y);
                 
                    pCursorOffset.X = pCursor.X - pCursorLastCoordinate.X;
              
                    pCursorOffset.Y = pCursor.Y - pCursorLastCoordinate.Y;
                    ctrl.Left = pCtrlLastCoordinate.X + pCursorOffset.X;
                    ctrl.Top = pCtrlLastCoordinate.Y + pCursorOffset.Y;
                }

            }
        }
 
        private void MouseUp(object sender, MouseEventArgs e)
        {
            if (Containe == null)
            {
                return;
            }
            if (this.IsMoving)
            {
                if (pCursorOffset.X == 0 && pCursorOffset.Y == 0)
                {
                    return;
                }
                if ((pCtrlLastCoordinate.X + pCursorOffset.X + ctrl.Width) > 0)
                {
                    ctrl.Left = pCtrlLastCoordinate.X + pCursorOffset.X;
                }
                else
                {
                    ctrl.Left = 0;
                }
                if ((pCtrlLastCoordinate.Y + pCursorOffset.Y + ctrl.Height) > 0)
                {
                    ctrl.Top = pCtrlLastCoordinate.Y + pCursorOffset.Y;
                }
                else
                {
                    ctrl.Top = 0;
                }
                pCursorOffset.X = 0;
                pCursorOffset.Y = 0;
            }
        }
        #endregion
        #region 建構函式
        /// <summary>
        /// 獲取被移動控制元件物件和容器物件
        /// </summary>
        /// <param name="c">被設定為可執行時移動的控制元件</param>
        /// <param name="parentContain">可移動控制元件的容器</param>
        public ControlMoveResize(Control c, ScrollableControl parentContain)
        {
            ctrl = c;
            this.Containe = parentContain;
            ctrl.MouseDown += new MouseEventHandler(MouseDown);
            ctrl.MouseMove += new MouseEventHandler(MouseMove);
            ctrl.MouseUp += new MouseEventHandler(MouseUp);
        }
        #endregion