C# 圖片框跟隨滑鼠移動

  　   先貼上代碼

　　　private bool isMouseDown = false;
        private Point mouseOffset; //記錄滑鼠指標的座標

        private void PicBox_MouseDown(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                mouseOffset.X = e.X;
                mouseOffset.Y = e.Y;
                isMouseDown = true;
            }
        }

        private void PicBox_MouseMove(object sender, MouseEventArgs e)
        {
            if (isMouseDown)
            {
                int left = PicBox.Left + e.X - mouseOffset.X;
                int top = PicBox.Top + e.Y - mouseOffset.Y;
                PicBox.Location = new Point(left,top);
            }
        }

        private void PicBox_MouseUp(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                isMouseDown = false;
            }
        }

 

 

　　 事件中的 MouseEventArgs e ：

　　根據e得到的座標，不是滑鼠相對與Form左上方的座標，而是相對於圖片框的左上方座標,所以算滑鼠位移量的時候，只要計算兩次事件對象e中的座標的差值！

　　儲存滑鼠按下時相對於圖片框左上方的座標

                mouseOffset.X = e.X;
                mouseOffset.Y = e.Y;

　　移動時得到位移量

                e.X - mouseOffset.X;
                e.Y - mouseOffset.Y;

     算出圖片框的新位置

                int left = PicBox.Left + e.X - mouseOffset.X;
                int top = PicBox.Top + e.Y - mouseOffset.Y;