ExcelHelper----根据指定样式的数据，生成excel（一个sheet1页）文件流

 /// <summary>
    /// Excel导出类
    /// </summary>
    public class ExcelHelper
    {
        /// <summary>
        /// 根据指定样式的数据，生成excel（一个sheet1页）文件流
        /// </summary>
        /// <param name="data">待导出数据的数组（包括隐藏的数据）</param>
        /// <param name="title">The title.</param>
        /// <param name="header">The header.</param>
        /// <param name="isShowRowNo">.如果定义为null或者empty,那么表示不需要增加序号列</param>
        /// <param name="colVisibleFlagArray">待导出数据的没列的隐藏标识</param>
        /// <param name="autosize">自动单元格宽度调整</param>
        /// <returns>MemoryStream.</returns>
        public static MemoryStream ExportFromArray(string[][] data, string title, string[] header, bool isShowRowNo, bool[] colVisibleFlagArray,bool autosize = true)
        {
            string[][] newdata = new string[data.Length][];
            List<List<string>> newlist = new List<List<string>>();
            List<string> newheader = new List<string>(); 
            //虑隐藏的数据：
            //过滤隐藏的数据头
            for (int i = 0; i < colVisibleFlagArray.Length; i++)
            {
                if (colVisibleFlagArray[i] == true)
                {
                    newheader.Add(header[i]);
                }
            }
            //过滤隐藏列的数据
            for (int j = 0; j < data.Length; j++)
            {
                newdata[j] = new string[newheader.Count];
               //当前列数
                int cnt = 0;
                //只添加加显示列的数据
                for (int i = 0; i < colVisibleFlagArray.Length; i++)
                {
                    if (colVisibleFlagArray[i] == true)
                    {
                        newdata[j][cnt] = data[j][i];
                        cnt++;
                    }
                }
            } 
            //如果显示序号，序号列头指定为“序号”；否则不输出列头
            string RowNo = isShowRowNo ? "序号" : null;
            MemoryStream stream = new MemoryStream();
            ExportExcelFromData instance = new ExportExcelFromData();
            SheetDefine sheet=new SheetDefine("sheet1", title, RowNo, newheader.ToArray(), newdata);
            sheet.AutoSizeColumn = autosize;
            instance.AddSheet(sheet);

            instance.WriteExcel(stream);
  
            return stream;
        }
    }