设置分页页码

        /// <summary>
        /// 设置分页页码
        /// </summary>
        /// <param name="pageNum">当前页码</param>
        /// <param name="pageCount">总页数</param>
        /// <param name="sideNum">每页显示条数</param>
        /// <param name="startNum">开始页码</param>
        /// <param name="endNum">结束页码</param>
        public static void calcPage(int pageNum, int pageCount, int sideNum, ref int startNum, ref int endNum)
        {
            if (pageCount <= sideNum)
            {
                endNum = pageCount;
            }
            else
            {
                if ((sideNum + pageNum) >= pageCount)
                {
                    endNum = pageCount;
                }
                else
                {
                    endNum = sideNum + pageNum;
                    if ((sideNum + pageNum) <= (2 * sideNum + 1))
                    {
                        if ((2 * sideNum + 1) >= pageCount)
                        {
                            endNum = pageCount;
                        }
                        else
                        {
                            endNum = 2 * sideNum + 1;
                        }
                    }
                    else
                    {
                        endNum = sideNum + pageNum;
                    }
                }
            }

            if (pageNum <= sideNum)
            {
                startNum = 1;
            }
            else
            {
                if ((pageNum + sideNum) >= pageCount)
                {
                    if ((2 * sideNum + 1) >= pageCount)
                    {
                        if ((pageCount - 2 * sideNum) >= 1)
                        {
                            startNum = pageCount - 2 * sideNum;
                        }
                        else
                        {
                            startNum = 1;
                        }
                    }
                    else
                    {
                        startNum = pageCount - 2 * sideNum;
                    }
                }
                else
                {
                    if ((pageNum - sideNum) >= 1)
                    {
                        startNum = pageNum - sideNum;
                    }
                    else
                    {
                        startNum = 1;
                    }
                }
            }
        }