C#移動及改變控件大小

//代碼比較簡單，就不多解析了。  

      #region 移動窗體保存數據

        Point mouseOff;//鼠標移動位置變量
        bool leftFlag; //標志是否為左鍵
        bool largeFlag; //標志是否同時改變寬度及高度
        bool widthFlag; //標志是否改變寬度
        bool heightFlag;//標志是否改變高度

        /// <summary>
        /// 鼠標移動
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void Form1_MouseMove(object sender, MouseEventArgs e)
        {
            Point mouseSet = Control.MousePosition;
            if (leftFlag)
            {
                //改變寬高
                if (largeFlag)
                {
                    int dw = mouseSet.X - this.Location.X;
                    int dh = mouseSet.Y - this.Location.Y;
                    this.Width = dw;
                    this.Height = dh;
                }
                //改變寬度
                else if (widthFlag)
                {
                    int dw = mouseSet.X - this.Location.X;
                    this.Width = dw;
                }
                //改變高度
                else if (heightFlag)
                {
                    int dh = mouseSet.Y - this.Location.Y;
                    this.Height = dh;
                }
                //移動位置
                else
                {
                    mouseSet.Offset(mouseOff.X, mouseOff.Y); //設置移動后的位置
                    this.Location = mouseSet;
                }
            }
            else
            {
                //設置改變窗體寬高的標志
                if ((this.Location.X + this.Width - mouseSet.X) < 10 && (this.Location.Y + this.Height - mouseSet.Y) < 10)
                {
                    this.Cursor = Cursors.SizeNWSE;
                    largeFlag = true;
                }
                //設置改變窗體寬度的標志
                else if ((this.Location.X + this.Width - mouseSet.X) < 10)
                {
                    this.Cursor = Cursors.SizeWE;
                    widthFlag = true;
                }
                //設置改變窗體高度的標志
                else if ((this.Location.Y + this.Height - mouseSet.Y) < 10)
                {
                    this.Cursor = Cursors.SizeNS;
                    heightFlag = true;
                }
                //設置移動位置的標志
                else
                {
                    this.Cursor = Cursors.Default;
                    largeFlag = false;
                    widthFlag = false;
                    heightFlag = false;
                }
            }
        }

        /// <summary>
        /// 鼠標按下
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void Form1_MouseDown(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                mouseOff = new Point(-e.X, -e.Y); //得到變量的值
                leftFlag = true;                  //點擊左鍵按下時標注為true;
            }
        }
        /// <summary>
        /// 鼠標彈起
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void Form1_MouseUp(object sender, MouseEventArgs e)
        {
            if (leftFlag)
            {
                
                leftFlag = false;//釋放鼠標后標注為false;
            }
        }
        #endregion