winform中Imagelist属性ImageKey的问题？？？？？

Question

代码如下： 
MemoryStream ms = new MemoryStream((Byte[])sdr["oleImg"]);
                            Image c = Image.FromStream(ms, true);
                            this.imageList1.Images.Add(sdr["AutoId"].ToString(),c);
                            listViewSmallImg.LargeImageList = imageList1;
                            listViewSmallImg.Items.Add("", sdr["oleImg"].ToString(),i);
sdr["AutoId"].ToString()为A
现在listViewSmallImg_SelectedIndexChanged事件中我想得到A，弄了大半天得不到。不知道应该怎样得到这个红色行里
sdr["AutoId"].ToString()的值？？？？？