点击按键时的图片切换

private bool fx = false;
        private void button2_Click(object sender, EventArgs e)
        {
            if (fx == false)  //自带的串口来判断   如果不为真就打开串口
            {
                button2.BackgroundImage = Properties.Resources.comconnet;
                //控件名.控件的图片属性=Properties.Resources.图片名
                fx = true;

            }
            else
            {
                button2.BackgroundImage = Properties.Resources.comconnetno;
                fx = false;

            }

               
        }