Point mouseOff;//鼠标移动位置变量        bool leftFlag;//标签是否为左键        private void Form1_MouseDown(object sender, MouseEventArgs e)        {            if (e.Button == MouseButtons.Left)            {                mouseOff = new Point(-e.X, -e.Y); //得到变量的值                leftFlag = true;                  //点击左键按下时标注为true;            }        }        private void Form1_MouseMove(object sender, MouseEventArgs e)        {            if (leftFlag)            {                Point mouseSet = Control.MousePosition;                mouseSet.Offset(mouseOff.X, mouseOff.Y);  //设置移动后的位置                Location = mouseSet;            }        }        private void Form1_MouseUp(object sender, MouseEventArgs e)        {            if (leftFlag)            {                leftFlag = false;//释放鼠标后标注为false;            }        }