excel数据导入数据库

using (FileStream fs = File.OpenRead(@"D:成绩管理名单.xls"))
            {
                IWorkbook wk = new HSSFWorkbook(fs);//根据文件流创建workbook
                if (wk.NumberOfSheets > 0)
                {
                    ISheet sheet = wk.GetSheetAt(0);//创建工作表
                    //学号    姓名    性别    出生年月  专业
                    for (int r = 1; r <= sheet.LastRowNum; r++)//r=1，从第1行开始读取，而不是第0行，第0行是列名
                    {
                        #region 获取excel数据
                        IRow row = sheet.GetRow(r);
                        int stuid;
                        if (row.GetCell(0).CellType==CellType.BLANK)//主键stuid不允许空，若为空则跳过该行数据
                        {
                            continue;
                        }
                        else
                        {
                            stuid = (int)row.GetCell(0).NumericCellValue;
                        }
                        string name = row.GetCell(1) == null ? null : row.GetCell(1).StringCellValue;
                        string gender = row.GetCell(2)==null ? null: row.GetCell(2).StringCellValue;
                        string birth = row.GetCell(3) == null? null : row.GetCell(3).StringCellValue;
                        string specialty = row.GetCell(4)==null ? null : row.GetCell(4).StringCellValue;
                        #endregion                        

                        string sql = "insert into ceshi values(@stuid,@name,@birth,@gender,@specialty)";
                        SqlParameter[] para = new SqlParameter[]{
                            new SqlParameter("@stuid",stuid),
                            //空值在C#中是null，但通过sql语句向数据库中插入null值应为DBNull.Value
                            new SqlParameter("@name",name==null?DBNull.Value:(object)name),
                            new SqlParameter("@birth",birth==null?DBNull.Value:(object)birth),
                            new SqlParameter("@gender",gender==null?DBNull.Value:(object)gender),
                            new SqlParameter("@specialty",specialty==null?DBNull.Value:(object)specialty),                
                        };
                        using (cmd = new SqlCommand(sql, GetConn()))
                        {
                            if (para!=null)
                            {
                            cmd.Parameters.AddRange(para);                                
                            }
                            cmd.ExecuteNonQuery();
                        }
                    }
                    MessageBox.Show("导入成功");
                }
            }