Asp.net 導出Excel

// localizedHeaders 用來轉換英文列到中文列
// trimUnlocalizedColumn 用來將隱藏的列，未本地化的列刪除掉

public static class ResponseHelper

    {

        public static void ResponseExcel(string tempFolder,

            DataTable dt,

            Dictionary<string, LocalizedHeader> localizedHeaders,

            bool trimUnlocalizedColumn,

            string fileName,

            string sheetName)

        {

            LocalizedColumnName(dt, localizedHeaders, trimUnlocalizedColumn);

            if (!Directory.Exists(tempFolder))

            {

                Directory.CreateDirectory(tempFolder);

            }

            if (string.IsNullOrEmpty(fileName))

            {

                fileName = Guid.NewGuid() + ".xls";

            }

            var excelPath = Path.Combine(tempFolder, fileName);

            using (ExcelHelper helper = new ExcelHelper(excelPath))

            {

                helper.DataTableToExcel(dt, sheetName ?? "Sheet1", true);

            }

            HttpContext.Current.Response.Clear();

            HttpContext.Current.Response.AppendHeader("Content-Disposition", "attachment;filename=" + fileName);

            HttpContext.Current.Response.Charset = "UTF-8";

            HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.UTF8;

            HttpContext.Current.Response.ContentType = "application/ms-excel";

            HttpContext.Current.Response.WriteFile(excelPath);

            HttpContext.Current.Response.End();

        }

        private static void LocalizedColumnName(DataTable dt, Dictionary<string, LocalizedHeader> localizedHeaders, bool trimUnlocalizedColumn)

        {

            if (localizedHeaders == null || localizedHeaders.Count == 0)

            {

                return;

            }

            var unlocalizedColumns = new List<string>();

            foreach (DataColumn column in dt.Columns)

            {

                if (localizedHeaders.ContainsKey(column.ColumnName))

                {

                    column.ColumnName = localizedHeaders[column.ColumnName].LocalizedName;

                }

                else

                {

                    unlocalizedColumns.Add(column.ColumnName);

                }

            }

            if (trimUnlocalizedColumn)

            {

                foreach (var unlocalizedColumn in unlocalizedColumns)

                {

                    dt.Columns.Remove(dt.Columns[unlocalizedColumn]);

                }

            }

            foreach (var localizedHeader in localizedHeaders)

            {

                 if (dt.Columns.Contains(localizedHeader.Value.LocalizedName)

                    && localizedHeader.Value.ColumnIndex < dt.Columns.Count )

                {

                {

                    dt.Columns[localizedHeader.Value.LocalizedName].SetOrdinal(localizedHeader.Value.ColumnIndex);

                }

            }

        }

    }

    public class LocalizedHeader

    {

        public string OrignalName { get; set; }

        public string LocalizedName { get; set; }

        public int ColumnIndex { get; set; }

    }

==================================================================================================================
== Excel幫助類，調用NPOI組件
==================================================================================================================
public  class ExcelHelper : IDisposable
    {
         private  readonly  string _fileName;  // 文件名
         private IWorkbook _workbook;
         private FileStream _fs;
         private  bool _disposed;

         public ExcelHelper(  string fileName)
        {
            _fileName = fileName;
            _disposed =  false;
        }

         ///   <summary>
         ///  將DataTable數據導入到excel中
         ///   </summary>
         ///   <param name=" data">  要導入的數據  </param>
         ///   <param name=" isColumnWritten"> DataTable的列名是否要導入  </param>
         ///   <param name=" sheetName">  要導入的excel的sheet的名稱  </param>
         ///   <returns>  導入數據行數(包含列名那一行)  </returns>
         public  int DataTableToExcel( DataTable data,  string sheetName,  bool isColumnWritten)
        {
             int i;
             int j;
             int count;
            ISheet sheet;

            _fs =  new FileStream(_fileName, FileMode .OpenOrCreate, FileAccess.ReadWrite);
             if (_fileName.IndexOf(  " .xlsx ") >  0)  //  2007版本
                _workbook =  new XSSFWorkbook();
             else  if (_fileName.IndexOf(  " .xls ") >  0)  //  2003版本
                _workbook =  new HSSFWorkbook();

             try
            {
                 if (_workbook !=  null)
                {
                    sheet = _workbook.CreateSheet(sheetName);
                }
                 else
                {
                     return - 1;
                }

                 if (isColumnWritten ==  true)  // 寫入DataTable的列名
                {
                    IRow row = sheet.CreateRow( 0);
                     for (j =  0; j < data.Columns.Count; ++j)
                    {
                        row.CreateCell(j).SetCellValue(data.Columns[j].ColumnName);
                    }
                    count =  1;
                }
                 else
                {
                    count =  0;
                }

                 for (i =  0; i < data.Rows.Count; ++i)
                {
                    IRow row = sheet.CreateRow(count);
                     for (j =  0; j < data.Columns.Count; ++j)
                    {
                        row.CreateCell(j).SetCellValue(data.Rows[i][j].ToString());
                    }
                    ++count;
                }
                _workbook.Write(_fs);  // 寫入到excel
                 return count;
            }
             catch ( Exception ex)
            {
                Console.WriteLine(  " Exception:  " + ex.Message);
                 return - 1;
            }
        }

         ///   <summary>
         ///  將excel中的數據導入到DataTable中
         ///   </summary>
         ///   <param name=" sheetName">  excel工做薄sheet的名稱  </param>
         ///   <param name=" isFirstRowColumn"> 第一行是不是DataTable的列名  </param>
         ///   <returns>  返回的DataTable </returns>
         public DataTable ExcelToDataTable(  string sheetName,  bool isFirstRowColumn)
        {
            ISheet sheet =  null;
            DataTable data =  new DataTable();
             int startRow =  0;
             try
            {
                _fs =  new FileStream(_fileName, FileMode .Open, FileAccess .Read);
                 if (_fileName.IndexOf(  " .xlsx ") >  0)  //  2007版本
                    _workbook =  new XSSFWorkbook(_fs);
                 else  if (_fileName.IndexOf(  " .xls ") >  0)  //  2003版本
                    _workbook =  new HSSFWorkbook(_fs);

                 if (sheetName !=  null)
                {
                    sheet = _workbook.GetSheet(sheetName);
                     if (sheet ==  null)  // 若是沒有找到指定的sheetName對應的sheet，則嘗試獲取第一個sheet
                    {
                        sheet = _workbook.GetSheetAt( 0);
                    }
                }
                 else
                {
                    sheet = _workbook.GetSheetAt( 0);
                }
                 if (sheet !=  null)
                {
                    IRow firstRow = sheet.GetRow( 0);
                     int cellCount = firstRow.LastCellNum;  // 一行最後一個cell的編號 即總的列數

                     if (isFirstRowColumn)
                    {
                         for (  int i = firstRow.FirstCellNum; i < cellCount; ++i)
                        {
                            ICell cell = firstRow.GetCell(i);
                             if (cell !=  null)
                            {
                                 string cellValue = cell.ToString();
                                DataColumn column =  new DataColumn (cellValue);
                                data.Columns.Add(column);
                            }
                        }
                        startRow = sheet.FirstRowNum +  1;
                    }
                     else
                    {
                        startRow = sheet.FirstRowNum;
                    }

                     // 最後一列的標號
                     int rowCount = sheet.LastRowNum;
                     for (  int i = startRow; i <= rowCount; ++i)
                    {
                        IRow row = sheet.GetRow(i);
                         if (row ==  null)  continue;  // 沒有數據的行默認是null　　　　　　　

                        DataRow dataRow = data.NewRow();
                         for (  int j = row.FirstCellNum; j < cellCount; ++j)
                        {
                            ICell cell = row.GetCell(j);
                             if (cell.CellType == CellType.Numeric)
                            {
                                 // NPOI中數字和日期都是NUMERIC類型的，這裏對其進行判斷是不是日期類型
                                 if ( DateUtil.IsCellDateFormatted(cell))  // 日期類型
                                {
                                    dataRow[j] = cell.DateCellValue;
                                }
                                 else // 其餘數字類型
                                {
                                    dataRow[j] = cell.NumericCellValue;
                                }
                            }
                             else  if (cell.CellType == CellType.Blank)  // 空數據類型
                            {
                                dataRow[j] =  "";
                            }
                             else  if (cell.CellType == CellType.Formula)  // 公式類型
                            {
                                HSSFFormulaEvaluator eva =  new HSSFFormulaEvaluator(_workbook);
                                dataRow[j] = eva.Evaluate(cell).StringValue;
                            }
                             else  // 其餘類型都按字符串類型來處理
                            {
                                dataRow[j] = cell.StringCellValue;
                            }
                        }
                        data.Rows.Add(dataRow);
                    }
                }

                 return data;
            }
             catch ( Exception ex)
            {
                Console.WriteLine(  " Exception:  " + ex.Message);
                 return  null;
            }
        }

         public  void Dispose()
        {
            Dispose(  true);
            GC.SuppressFinalize(  this);
        }

         protected  virtual  void Dispose(  bool disposing)
        {
             if (!  this._disposed)
            {
                 if (disposing)
                {
                     if (_fs !=  null)
                        _fs.Close();
                }

                _fs =  null;
                _disposed =  true;             }         }     }