ASP.NET使用NPOI类库导出Excel

/*
* 作者: 牛腩
* 创建时间: 2010-1-4 15:15:05
* Email: 164423073@qq.com
* 说明: 导出EXCEL的类，使用说明见：http://msdn.microsoft.com/zh-tw/ee818993.aspx
*/

using System;
using System.Collections.Generic;
using System.Data;
using System.IO;
using System.Linq;
using System.Web;
using NPOI;
using NPOI.HPSF;
using NPOI.HSSF;
using NPOI.HSSF.UserModel;
using NPOI.POIFS;
using NPOI.Util;

public class DataTableRenderToExcel
{
public static Stream RenderDataTableToExcel(DataTable SourceTable)
{
HSSFWorkbook workbook = new HSSFWorkbook();
MemoryStream ms = new MemoryStream();
HSSFSheet sheet = workbook.CreateSheet();
HSSFRow headerRow = sheet.CreateRow(0);

// handling header.
foreach (DataColumn column in SourceTable.Columns)
headerRow.CreateCell(column.Ordinal).SetCellValue(column.ColumnName);

// handling value.
int rowIndex = 1;

foreach (DataRow row in SourceTable.Rows)
{
HSSFRow dataRow = sheet.CreateRow(rowIndex);

foreach (DataColumn column in SourceTable.Columns)
{
dataRow.CreateCell(column.Ordinal).SetCellValue(row[column].ToString());
}

rowIndex++;
}

workbook.Write(ms);
ms.Flush();
ms.Position = 0;

sheet = null;
headerRow = null;
workbook = null;

return ms;
}

public static void RenderDataTableToExcel(DataTable SourceTable, string FileName)
{
MemoryStream ms = RenderDataTableToExcel(SourceTable) as MemoryStream;
FileStream fs = new FileStream(FileName, FileMode.Create, FileAccess.Write);
byte[] data = ms.ToArray();

fs.Write(data, 0, data.Length);
fs.Flush();
fs.Close();

data = null;
ms = null;
fs = null;
}

public static DataTable RenderDataTableFromExcel(Stream ExcelFileStream, string SheetName, int HeaderRowIndex)
{
HSSFWorkbook workbook = new HSSFWorkbook(ExcelFileStream);
HSSFSheet sheet = workbook.GetSheet(SheetName);

DataTable table = new DataTable();

HSSFRow headerRow = sheet.GetRow(HeaderRowIndex);
int cellCount = headerRow.LastCellNum;

for (int i = headerRow.FirstCellNum; i < cellCount; i++)
{
DataColumn column = new DataColumn(headerRow.GetCell(i).StringCellValue);
table.Columns.Add(column);
}

int rowCount = sheet.LastRowNum;

for (int i = (sheet.FirstRowNum + 1); i < sheet.LastRowNum; i++)
{
HSSFRow row = sheet.GetRow(i);
DataRow dataRow = table.NewRow();

for (int j = row.FirstCellNum; j < cellCount; j++)
dataRow[j] = row.GetCell(j).ToString();
}

ExcelFileStream.Close();
workbook = null;
sheet = null;
return table;
}

public static DataTable RenderDataTableFromExcel(Stream ExcelFileStream, int SheetIndex, int HeaderRowIndex)
{
HSSFWorkbook workbook = new HSSFWorkbook(ExcelFileStream);
HSSFSheet sheet = workbook.GetSheetAt(SheetIndex);

DataTable table = new DataTable();

HSSFRow headerRow = sheet.GetRow(HeaderRowIndex);
int cellCount = headerRow.LastCellNum;

for (int i = headerRow.FirstCellNum; i < cellCount; i++)
{
DataColumn column = new DataColumn(headerRow.GetCell(i).StringCellValue);
table.Columns.Add(column);
}

int rowCount = sheet.LastRowNum;

for (int i = (sheet.FirstRowNum + 1); i < sheet.LastRowNum; i++)
{
HSSFRow row = sheet.GetRow(i);
DataRow dataRow = table.NewRow();

for (int j = row.FirstCellNum; j < cellCount; j++)
{
if (row.GetCell(j) != null)
dataRow[j] = row.GetCell(j).ToString();
}

table.Rows.Add(dataRow);
}

ExcelFileStream.Close();
workbook = null;
sheet = null;
return table;
}

/// <summary>读取excel
/// 默认第一行为标头
/// </summary>
/// <param name="path">excel文档路径</param>
/// <returns></returns>
public static DataTable RenderDataTableFromExcel(string path) {
DataTable dt = new DataTable();

HSSFWorkbook hssfworkbook;
using (FileStream file = new FileStream(path, FileMode.Open, FileAccess.Read))
{
hssfworkbook = new HSSFWorkbook(file);
}
HSSFSheet sheet = hssfworkbook.GetSheetAt(0);
System.Collections.IEnumerator rows = sheet.GetRowEnumerator();

HSSFRow headerRow = sheet.GetRow(0);
int cellCount = headerRow.LastCellNum;

for (int j = 0; j < cellCount; j++)
{
HSSFCell cell = headerRow.GetCell(j);
dt.Columns.Add(cell.ToString());
}

for (int i = (sheet.FirstRowNum + 1); i <= sheet.LastRowNum; i++)
{
HSSFRow row = sheet.GetRow(i);
DataRow dataRow = dt.NewRow();

for (int j = row.FirstCellNum; j < cellCount; j++)
{
if (row.GetCell(j) != null)
dataRow[j] = row.GetCell(j).ToString();
}

dt.Rows.Add(dataRow);
}

//while (rows.MoveNext())
//{
// HSSFRow row = (HSSFRow)rows.Current;
// DataRow dr = dt.NewRow();

// for (int i = 0; i < row.LastCellNum; i++)
// {
// HSSFCell cell = row.GetCell(i);

// if (cell == null)
// {
// dr[i] = null;
// }
// else
// {
// dr[i] = cell.ToString();
// }
// }
// dt.Rows.Add(dr);
//}

return dt;
}
}