首先需要下载一个NPOI.dll  
下载地址：http://download.csdn.net/detail/president810/9503038

using System;

using System.Collections.Generic;

using System.IO;
//引用NPOI

using NPOI.HSSF.UserModel;

using NPOI.SS.UserModel;

namespace Sola.ExportTakeClass

{

public class ExportToExcelUtil

{

private string _excelPath = "";

private IWorkbook workbook;

private ISheet sheet;

private int row = ;

private IList<string> sheetList = new List<string>();

public ExportToExcelUtil(string excelPath,IList<string> sheetList)

{

_excelPath = excelPath;

this.sheetList = sheetList;

ExcelFormat();

}

/// <summary>

/// 遍历sheet 并添加到excel

/// </summary>

private void ExcelFormat()

{

try

{

workbook = new HSSFWorkbook();

foreach (var sheetname in sheetList)

{

workbook.CreateSheet(sheetname);

}

}

catch

{

GC.Collect();

GC.Collect();

}

}

/// <summary>

/// 将头部列表添加至 指定的sheet页

/// </summary>

/// <param name="titleList"></param>

/// <param name="sheetName"></param>

public void SetHead(IList<string> titleList,string sheetName)

{

row = ;

sheet = workbook.GetSheet(sheetName);

IRow headerRow = sheet.CreateRow(row);

int col = ;

foreach (string t in titleList)

{

headerRow.CreateCell(col).SetCellValue(t);

col++;

}

}

/// <summary>

/// 将数据写入指定的 sheet页

/// </summary>

/// <param name="valueList"></param>

/// <param name="sheetName"></param>

public void WriteExcel(IList<string> valueList, string sheetName)

{

int col = ;

sheet = workbook.GetSheet(sheetName);

row++;

IRow itemRow = sheet.CreateRow(row);

foreach (string v in valueList)

{

itemRow.CreateCell(col).SetCellValue(v);

col++;

}

}

public void Close()

{

try

{

FileStream file = new FileStream(_excelPath, FileMode.Create);

workbook.Write(file);

file.Close();

workbook.Clear();

}

finally

{

GC.Collect();

GC.Collect();

}

}

}

}