List<int> Loc=new List<int>();

//假设panel中有4个PictureBox 
foreach (Control c in pl.Controls) 
{
if (c is PictureBox && c.Name !="pBx_bjl") 
{ 
    Loc.Add(c.Location.X);
}}
            Loc.Sort();//
           // Loc[0]就是最小的，Loc已经排序了，你就知道怎么处理了吧

      //首先要創建一個實現ICompare的類，用來排序
        public class PictureBoxComparer : IComparer<PictureBox>
        {
            #region IComparer<PictureBox> 成员

            public int Compare(PictureBox x, PictureBox y)
            {
                if (x.Location.X > y.Location.X) 
                    return 1;
                else if (x.Location.X < y.Location.X)
                    return -1;
                else
                {
                    return 0;
                }
            }

            #endregion
        }


            //下面是使用list存儲並排序及取值的代碼
            List<PictureBox> list=new List<PictureBox>();
            foreach (Control c in panel1.Controls)
            {
                if (c is PictureBox)
                {
                    list.Add((PictureBox) c);
                }
            }
            //下面代碼是對list進行排序，會以升序來排列。
            list.Sort((IComparer<PictureBox>)new PictureBoxComparer());

            //下面的代碼可以枚舉所有的pictureBox
            foreach (PictureBox pic in list)
            {
                MessageBox.Show(pic.Location.X.ToString());
            }
            //獲取最大的X值的
            PictureBox MaxXPicBox = list[list.Count - 1];
            //獲取最小的X值的
            PictureBox MinXPicBox = list[0];

        public class PictureBoxComparer : IComparer
        {
            #region IComparer 成员

            public int Compare(object x, object y)
            {
                PictureBox picX = (PictureBox)x;
                PictureBox picY = (PictureBox) y;
                if (picX.Location.X > picY.Location.X)
                    return 1;
                else if (picX.Location.X < picY.Location.X)
                    return -1;
                else
                {
                    return 0;
                }
            }

            #endregion
        }

            ArrayList list = new ArrayList();
            foreach (Control c in panel1.Controls)
            {
                if (c is PictureBox)
                {
                    list.Add(c);
                }
            }
            //下面代碼是對list進行排序，會以升序來排列。
            list.Sort((IComparer)new PictureBoxComparer());

            //下面的代碼可以枚舉所有的pictureBox
            for (int i = 0; i < list.Count;i++ )
            {
                PictureBox pic = (PictureBox)list[i];
                MessageBox.Show(pic.Location.X.ToString());
            }
            //獲取最大的X值的
            PictureBox MaxXPicBox = (PictureBox) list[list.Count - 1];
            //獲取最小的X值的
            PictureBox MinXPicBox = (PictureBox)list[0];