OpenXmlSdk导出Excel

　　感觉OpenXmlSdk的语法真的不是很友好。研究了半天，只实现了简单的导出功能。对于单元格样式的设置暂时还是搞明白，网上的资料真的很少，官方文档是英文的。中文的文章大都是用工具（Open XML SDK 2.0 Productivity Tool）搞出来的，反正在我这是不管用。最终还是回到了NPOI 的怀抱。

　　最后还是把这点代码记录一下，以后有时间再继续研究吧。

 using System;
 using System.Data;
 using System.IO;
 using System.Web;
 using DocumentFormat.OpenXml;
 using DocumentFormat.OpenXml.Packaging;
 using DocumentFormat.OpenXml.Spreadsheet;

 public static class ExportHelper
 {
     /// <summary>
     /// 导出Excel文件
     /// </summary>
     /// <param name="fileName"></param>
     /// <param name="dataSet">DataSet中每个DataTable生成一个Sheet</param>
     public static void ExportExcel(string fileName, DataSet dataSet)
     {
         if (dataSet.Tables.Count == )
         {
             return;
         }

         using (MemoryStream stream = DataTable2ExcelStream(dataSet))
         {
             FileStream fs = new FileStream(fileName, FileMode.CreateNew);
             stream.WriteTo(fs);
             fs.Flush();
             fs.Close();
         }
     }

     public static void ExportExcel(string fileName, DataTable dataTable)
     {
         DataSet dataSet = new DataSet();
         dataSet.Tables.Add(dataTable);
         ExportExcel(fileName, dataSet);
     }

     /// <summary>
     /// Web导出Excel文件
     /// </summary>
     /// <param name="fileName"></param>
     /// <param name="dataSet">DataSet中每个DataTable生成一个Sheet</param>
     public static void ResponseExcel(string fileName, DataSet dataSet)
     {
         if (dataSet.Tables.Count == )
         {
             return;
         }

         using (MemoryStream stream = DataTable2ExcelStream(dataSet))
         {
             ExportExcel(fileName, stream);
         }
     }

     public static void ResponseExcel(string fileName, DataTable dataTable)
     {
         DataSet dataSet = new DataSet();
         dataSet.Tables.Add(dataTable.Copy());
         ResponseExcel(fileName, dataSet);
     }

     private static void ExportExcel(string fileName, MemoryStream stream)
     {
         HttpContext.Current.Response.Clear();
         HttpContext.Current.Response.Charset = "UTF-8";
         HttpContext.Current.Response.AppendHeader("Content-Disposition", "attachment;filename= " + HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8));
         HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.UTF8;
         HttpContext.Current.Response.ContentType = "application/ms-excel";
         HttpContext.Current.Response.BinaryWrite(stream.ToArray());
         HttpContext.Current.Response.Flush();
         HttpContext.Current.Response.End();
     }

     private static MemoryStream DataTable2ExcelStream(DataSet dataSet)
     {
         MemoryStream stream = new MemoryStream();
         SpreadsheetDocument document = SpreadsheetDocument.Create(stream,
             SpreadsheetDocumentType.Workbook);

         WorkbookPart workbookPart = document.AddWorkbookPart();
         workbookPart.Workbook = new Workbook();

         Sheets sheets = document.WorkbookPart.Workbook.AppendChild(new Sheets());

         for (int i = ; i < dataSet.Tables.Count; i++)
         {
             DataTable dataTable = dataSet.Tables[i];
             WorksheetPart worksheetPart = document.WorkbookPart.AddNewPart<WorksheetPart>();
             worksheetPart.Worksheet = new Worksheet(new SheetData());

             Sheet sheet = new Sheet
             {
                 Id = document.WorkbookPart.GetIdOfPart(worksheetPart),
                 SheetId = (UInt32)(i + ),
                 Name = dataTable.TableName
             };
             sheets.Append(sheet);

             SheetData sheetData = worksheetPart.Worksheet.GetFirstChild<SheetData>();

             Row headerRow = CreateHeaderRow(dataTable.Columns);
             sheetData.Append(headerRow);

             for (int j = ; j < dataTable.Rows.Count; j++)
             {
                 sheetData.Append(CreateRow(dataTable.Rows[j], j + ));
             }
         }

         document.Close();

         return stream;
     }

     private static Row CreateHeaderRow(DataColumnCollection columns)
     {
         Row header = new Row();
         for (int i = ; i < columns.Count; i++)
         {
             Cell cell = CreateCell(i + , , columns[i].ColumnName, CellValues.String);
             header.Append(cell);
         }
         return header;
     }

     private static Row CreateRow(DataRow dataRow, int rowIndex)
     {
         Row row = new Row();
         for (int i = ; i < dataRow.Table.Columns.Count; i++)
         {
             Cell cell = CreateCell(i + , rowIndex, dataRow[i], GetType(dataRow.Table.Columns[i].DataType));
             row.Append(cell);
         }
         return row;
     }

     private static CellValues GetType(Type type)
     {
         if (type == typeof(decimal))
         {
             return CellValues.Number;
         }
         //if ((type == typeof(DateTime)))
         //{
         //    return CellValues.Date;
         //}
         return CellValues.SharedString;
     }

     private static Cell CreateCell(int columnIndex, int rowIndex, object cellValue, CellValues cellValues)
     {
         Cell cell = new Cell
         {
             CellReference = GetCellReference(columnIndex) + rowIndex,
             CellValue = new CellValue { Text = cellValue.ToString() },
             DataType = new EnumValue<CellValues>(cellValues),
             StyleIndex =
         };
         return cell;
     }

     private static string GetCellReference(int colIndex)
     {
         int dividend = colIndex;
         string columnName = String.Empty;

         while (dividend > )
         {
             int modifier = (dividend - ) % ;
             columnName = Convert.ToChar( + modifier) + columnName;
             dividend = (dividend - modifier) / ;
         }

         return columnName;
     }
 }