timer的问题(windows.forms.timer)

Question

最近没事设计一个电梯的模拟程序.在一个panel里面有2个picturebox.分别代表左边门和右边门.    
代码如下:
        private void timer1_Tick(object sender, EventArgs e)
        {            Point PL = new Point(this.pictureBox1.Location.X - 1, 0);    //PL代表左边门的位置   初始位置(0,0),  左边门往左,-1
            Point PR = new Point(this.pictureBox2.Location.X + 1, 0);    //PR代表右边门的位置   初始位置(92,0), 右边门往右,+1
            if (PL.X == -92)
            {
                timer1.Enabled = false;
            }
        }
问题是就是运行后它不会移动.已经设置为true,interval=10.

Answer 1

private void timer1_Tick(object sender,EventArgs e) 
{
    this.pictureBox1.Location.X-=1;
    this.pictureBox2.Location.X+=1;
    this.pictureBox1.Refresh();
    this.pictureBox2.Refresh();
    if   (this.pictureBox1.X== -92) 
    { 
        timer1.Enabled = false; 
    } 
}
//Refresh();//强制控件重绘