使用 NPOI 导出 Excel 文件

【NPOI简介】

NPOI 是 POI 项目的 .NET 版本。POI是一个开源的Java读写Excel、WORD等微软OLE2组件文档的项目。

使用 NPOI 你就可以在没有安装 Office 或者相应环境的机器上对 WORD/EXCEL 文档进行读写。NPOI是构建在POI 3.x版本之上的，它可以在没有安装Office的情况下对Word/Excel文档进行读写操作。

NPOI官方教程地址：http://tonyqus.sinaapp.com

googlecode：http://code.google.com/p/npoi/

codeplex：http://npoi.codeplex.com/

Excel 助手类：

using System;
using System.Data;
using System.IO;
using System.Text;
using System.Web;
using NPOI.HPSF;
using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;
using System.Collections.Generic;
using System.Collections;
namespace Weilog.Core.Document.Excel
{
/// <summary>
/// Excel 助手类。
/// </summary>
public class ExcelHelper
{

private void InitializeWorkbook(HSSFWorkbook hssfworkbook, string headerText)
{
hssfworkbook = new HSSFWorkbook();

//创建一个文档摘要信息实体。
DocumentSummaryInformation dsi = PropertySetFactory.CreateDocumentSummaryInformation();
dsi.Company = "Weilog Team"; //公司名称
hssfworkbook.DocumentSummaryInformation = dsi;

//创建一个摘要信息实体。
SummaryInformation si = PropertySetFactory.CreateSummaryInformation();
si.Subject = "Weilog 系统生成";
si.Author = "Weilog 系统";
si.Title = headerText;
si.Subject = headerText;
si.CreateDateTime = DateTime.Now;
hssfworkbook.SummaryInformation = si;

}

private static MemoryStream WriteToStream(HSSFWorkbook hssfworkbook)
{
//Write the stream data of workbook to the root directory
MemoryStream file = new MemoryStream();
hssfworkbook.Write(file);
return file;
}
//Export(DataTable table, string headerText, string sheetName, string[] columnName, string[] columnTitle)
/// <summary>
/// 向客户端输出文件。
/// </summary>
/// <param name="table">数据表。</param>
/// <param name="headerText">头部文本。</param>
/// <param name="sheetName"></param>
/// <param name="columnName">数据列名称。</param>
/// <param name="columnTitle">表标题。</param>
/// <param name="fileName">文件名称。</param>
public static void Write(DataTable table, string headerText, string sheetName, string[] columnName, string[] columnTitle, string fileName)
{
HttpContext context = HttpContext.Current;
context.Response.ContentType = "application/vnd.ms-excel";
context.Response.AddHeader("Content-Disposition", string.Format("attachment;filename={0}",HttpUtility.UrlEncode(fileName, Encoding.UTF8)));
context.Response.Clear();
HSSFWorkbook hssfworkbook = GenerateData(table, headerText, sheetName, columnName, columnTitle);
context.Response.BinaryWrite(WriteToStream(hssfworkbook).GetBuffer());
context.Response.End();
}
/// <summary>
///
/// </summary>
/// <param name="table"></param>
/// <param name="headerText"></param>
/// <param name="sheetName"></param>
/// <param name="columnName"></param>
/// <param name="columnTitle"></param>
/// <returns></returns>
public static HSSFWorkbook GenerateData(DataTable table, string headerText, string sheetName, string[] columnName, string[] columnTitle)
{
HSSFWorkbook hssfworkbook = new HSSFWorkbook();
ISheet sheet = hssfworkbook.CreateSheet(sheetName);

#region 设置文件属性信息

//创建一个文档摘要信息实体。
DocumentSummaryInformation dsi = PropertySetFactory.CreateDocumentSummaryInformation();
dsi.Company = "Weilog Team"; //公司名称
hssfworkbook.DocumentSummaryInformation = dsi;

//创建一个摘要信息实体。
SummaryInformation si = PropertySetFactory.CreateSummaryInformation();
si.Subject = "本文档由 Weilog 系统生成";
si.Author = " Weilog 系统";
si.Title = headerText;
si.Subject = headerText;
si.CreateDateTime = DateTime.Now;
hssfworkbook.SummaryInformation = si;

#endregion

ICellStyle dateStyle = hssfworkbook.CreateCellStyle();
IDataFormat format = hssfworkbook.CreateDataFormat();
dateStyle.DataFormat = format.GetFormat("yyyy-mm-dd");

#region 取得列宽

int[] colWidth = new int[columnName.Length];
for (int i = 0; i < columnName.Length; i++)
{
colWidth[i] = Encoding.GetEncoding(936).GetBytes(columnTitle[i]).Length;
}
for (int i = 0; i < table.Rows.Count; i++)
{
for (int j = 0; j < columnName.Length; j++)
{
int intTemp = Encoding.GetEncoding(936).GetBytes(table.Rows[i][columnName[j]].ToString()).Length;
if (intTemp > colWidth[j])
{
colWidth[j] = intTemp;
}
}
}

#endregion

int rowIndex = 0;
foreach (DataRow row in table.Rows)
{
#region 新建表，填充表头，填充列头，样式
if (rowIndex == 65535 || rowIndex == 0)
{
if (rowIndex != 0)
{
sheet = hssfworkbook.CreateSheet(sheetName + ((int)rowIndex / 65535).ToString());
}

#region 表头及样式
//if (!string.IsNullOrEmpty(headerText))
{
IRow headerRow = sheet.CreateRow(0);
headerRow.HeightInPoints = 25;
headerRow.CreateCell(0).SetCellValue(headerText);

ICellStyle headStyle = hssfworkbook.CreateCellStyle();
headStyle.Alignment = HorizontalAlignment.CENTER;
IFont font = hssfworkbook.CreateFont();
font.FontHeightInPoints = 20;
font.Boldweight = 700;
headStyle.SetFont(font);

headerRow.GetCell(0).CellStyle = headStyle;
//sheet.AddMergedRegion(new Region(0, 0, 0, dtSource.Columns.Count - 1));
sheet.AddMergedRegion(new NPOI.SS.Util.CellRangeAddress(0, 0, 0, table.Columns.Count - 1));
}
#endregion

#region 列头及样式
{
//HSSFRow headerRow = sheet.CreateRow(1);
IRow headerRow;
//if (!string.IsNullOrEmpty(headerText))
//{
//    headerRow = sheet.CreateRow(0);
//}
//else
//{
headerRow = sheet.CreateRow(1);
//}
ICellStyle headStyle = hssfworkbook.CreateCellStyle();
headStyle.Alignment = HorizontalAlignment.CENTER;
IFont font = hssfworkbook.CreateFont();
font.FontHeightInPoints = 10;
font.Boldweight = 700;
headStyle.SetFont(font);

for (int i = 0; i < columnName.Length; i++)
{
headerRow.CreateCell(i).SetCellValue(columnTitle[i]);
headerRow.GetCell(i).CellStyle = headStyle;
//设置列宽
if ((colWidth[i] + 1) * 256 > 30000)
{
sheet.SetColumnWidth(i, 10000);
}
else
{
sheet.SetColumnWidth(i, (colWidth[i] + 1) * 256);
}
}
/*
foreach (DataColumn column in dtSource.Columns)
{
headerRow.CreateCell(column.Ordinal).SetCellValue(column.ColumnName);
headerRow.GetCell(column.Ordinal).CellStyle = headStyle;

//设置列宽
sheet.SetColumnWidth(column.Ordinal, (arrColWidth[column.Ordinal] + 1) * 256);
}
* */
}
#endregion
//if (!string.IsNullOrEmpty(headerText))
//{
//    rowIndex = 1;
//}
//else
//{
rowIndex = 2;
//}

}
#endregion

#region 填充数据

IRow dataRow = sheet.CreateRow(rowIndex);
for (int i = 0; i < columnName.Length; i++)
{
ICell newCell = dataRow.CreateCell(i);

string drValue = row[columnName[i]].ToString();

switch (table.Columns[columnName[i]].DataType.ToString())
{
case "System.String"://字符串类型
if (drValue.ToUpper() == "TRUE")
newCell.SetCellValue("是");
else if (drValue.ToUpper() == "FALSE")
newCell.SetCellValue("否");
newCell.SetCellValue(drValue);
break;
case "System.DateTime"://日期类型
DateTime dateV;
DateTime.TryParse(drValue, out dateV);
newCell.SetCellValue(dateV);

newCell.CellStyle = dateStyle;//格式化显示
break;
case "System.Boolean"://布尔型
bool boolV = false;
bool.TryParse(drValue, out boolV);
if (boolV)
newCell.SetCellValue("是");
else
newCell.SetCellValue("否");
break;
case "System.Int16"://整型
case "System.Int32":
case "System.Int64":
case "System.Byte":
int intV = 0;
int.TryParse(drValue, out intV);
newCell.SetCellValue(intV);
break;
case "System.Decimal"://浮点型
case "System.Double":
double doubV = 0;
double.TryParse(drValue, out doubV);
newCell.SetCellValue(doubV);
break;
case "System.DBNull"://空值处理
newCell.SetCellValue("");
break;
default:
newCell.SetCellValue("");
break;
}

}

#endregion

rowIndex++;
}

return hssfworkbook;
}
}
}

使用的过程中需要将实体对象集合转换成 DataTable

使用方法：

#region 将指定的集合转换成数据表...

/// <summary>
/// 将指定的集合转换成DataTable。
/// </summary>
/// <param name="list">将指定的集合。</param>
/// <returns>返回转换后的DataTable。</returns>
public static DataTable ListToDataTable(IList list)
{
DataTable table = new DataTable();
if (list.Count > 0)
{
PropertyInfo[] propertys = list[0].GetType().GetProperties();
foreach (PropertyInfo pi in propertys)
{
Type pt = pi.PropertyType;
if ((pt.IsGenericType) && (pt.GetGenericTypeDefinition() == typeof(Nullable<>)))
{
pt = pt.GetGenericArguments()[0];
}
table.Columns.Add(new DataColumn(pi.Name, pt));
}

for (int i = 0; i < list.Count; i++)
{
ArrayList tempList = new ArrayList();
foreach (PropertyInfo pi in propertys)
{
object obj = pi.GetValue(list[i], null);
tempList.Add(obj);
}
object[] array = tempList.ToArray();
table.LoadDataRow(array, true);
}
}
return table;
}

#endregion

#region 导出数据...

private void ExportData(List<ProductInfo> productList)
{
var exportDataList =
(from productInfo in ProductList
new
{
Code = productInfo.Code,
Name = productInfo.Name,
DeptName = productInfo.DeptName,
ProjectName = productInfo.ProjectName,
CategoryName = productInfo.CategoryName,
Intro = productInfo.Intro,
Level = productInfo.Level,
Objective = productInfo.Objective
}).ToList();

DataTable table = ListToDataTable(exportDataList);
string[] strFields = { "Code", "Name", "DeptName", "ProjectName", "CategoryName", "Intro", "Level", "Objective" };
string[] strFieldsName = { "编码", "名称", "所属部门", "所属项目", "分类", "简介", "等级", "目标" };
ExcelHelper.Write(table, "产品表", "产品表", strFields, strFieldsName, "产品表.xls");
}

#endregion