panelPop是一个面板
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        private Point mouseOffset;
        private Boolean ismousedown = false;
        private void panelPop_MouseDown(object sender, MouseEventArgs e)
        {
            mouseOffset = new Point(-e.X, -e.Y);
            ismousedown = true; 
        }        private void panelPop_MouseMove(object sender, MouseEventArgs e)
        {
            if (ismousedown)
            {
                Point mousePos = Control.MousePosition;
                mousePos.Offset(mouseOffset.X, mouseOffset.Y);
                this.panelPop.Location = mousePos;
            }
        }        private void panelPop_MouseUp(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                ismousedown = false;
            }
        }
也不知道为啥 没效果