通过Aspose.Cells.dll组件，实现多sheet导出Xls

  /// <summary>
    /// Excel导出写入
    /// </summary>
    public class ExcelHelper
    {
        /// <summary>
        /// 当前行号【从0开始】
        /// </summary>
        public int rowIndex = 0;
        /// <summary>
        /// Excel实例
        /// </summary>
        private Workbook book = null;
        /// <summary>
        /// 当前工作表
        /// </summary>
        private Worksheet sheet = null;
        /// <summary>
        /// 返回当前sheet一共有多少列
        /// </summary>
        public int MaxColCount
        {
            get
            {
                return sheet.Cells.Columns.Count;
            }
        }
        /// <summary>
        /// 返回当前sheet一共有多少行
        /// </summary>
        public int MaxRowCount
        {
            get
            {
                return sheet.Cells.Rows.Count;
            }
        }
        /// <summary>
        /// 创建一个新的Excel
        /// </summary>
        public ExcelHelper()
        {
            book = new Workbook();
            sheet = book.Worksheets[0];
        }

        /// <summary>
        /// 创建一个新的Excel
        /// </summary>
        public ExcelHelper(string excelpath)
        {
            book = new Workbook();
            book.LoadData(excelpath);
        }
        /// <summary>
        /// 选择工作表
        /// </summary>
        /// <param name="index"></param>
        public bool SelectWorkSheet(int index)
        {
            if (book.Worksheets != null && book.Worksheets.Count > index)
            {
                sheet = book.Worksheets[0];
                return true;
            }
            return false;
        }
        /// <summary>
        /// 选择工作表
        /// </summary>
        /// <param name="index"></param>
        public bool SelectWorkSheet(string sheetName)
        {
            if (book.Worksheets != null && book.Worksheets[sheetName] != null)
            {
                sheet = book.Worksheets[sheetName];
                return true;
            }
            return false;
        }

        /// <summary>
        /// 添加工作薄
        /// </summary>
        /// <param name="sheetName">工作薄名称</param>
        /// <returns></returns>
        public bool AddSheet(string sheetName)
        {
            if (sheet.Name == "Sheet1")
            { 
                sheet.Name = sheetName;
                return true;
            }
            sheet = book.Worksheets.Add(sheetName);
            return sheet == null;
        }
        /// <summary>
        /// 保存
        /// </summary>
        /// <param name="filename"></param>
        public void Save(string filename)
        {
            book.Save(filename);
        }
        /// <summary>
        /// 保存
        /// </summary>
        /// <param name="filename"></param>
        public void Save(System.IO.Stream sw)
        {
            book.Save(sw,FileFormatType.Excel2003);
        }
        /// <summary>
        /// 写入数据
        /// </summary>
        /// <param name="colIndex">起始列号</param>
        /// <param name="datas">数据数组</param>
        public void WriteData(int colIndex, params string[] datas)
        {
            if (datas == null)
                return;
            foreach (string s in datas)
            {
                sheet.Cells[rowIndex, colIndex].PutValue(s); 
                colIndex++;
            }
        }

        /// <summary>
        /// 获取单元格的值
        /// </summary> 
        public string GetCellsValue(int colIndex)
        {
            Cell c = sheet.Cells[rowIndex, colIndex];
            if (c != null)
              return c.Value.ToString();
            return "";
        }
    }