用PictureBox的tag值回判断PictureBox的图片输出

用PictureBox的tag值来判断PictureBox的图片输出
我用PictureBox的tag值来判断PictureBox应该输出的图片。。
可是这样做不能显示？想请教下哪里出了问题！
tag值是已经输入的！

 public void RoomKind()
        {
            PictureBox PB = new PictureBox();
            if (PB.Tag == null)
            {
                return;
            }
            else //if (imageList1.Images.Count > 0)
           {
               switch (PB.Tag.ToString())
               {
                   case "Nomel":
                       {
                           PB.Image = imageList1.Images[0];

                       } return;
                   case "Book":
                       {
                           PB.Image = imageList1.Images[1];

                       } return;
                   case "Clink":
                       {
                           PB.Image = imageList1.Images[2];

                       } return;

                   case "vip":
                       {
                           PB.Image = imageList1.Images[3];

                       } return;
               }
           }
        }
        #endregion

------解决思路----------------------
你都是new 的一个pictureBox tag坑定是null