public Queue<Image>  QueueMethod() //队列
        {
            Queue<Image> strList = new Queue<Image>();
            foreach (var item in getPic(@"E:\pic1"))
            {
                strList.Enqueue(Image.FromFile(item));
            }
            return strList;
        }        private void button1_Click(object sender, EventArgs e)
        {
            
            pictureBox1.Image=QueueMethod().First<Image>();
            QueueMethod().Dequeue(); //怎么删除不了队列中首元素啊