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.NET NPOI导出Excel详解
NPOI，顾名思义，就是POI的.NET版本。那POI又是什么呢？POI是一套用Java写成的库，能够帮助开发者在没有安装微软Office的情况下读写Office的文件。
支持的文件格式包括xls, doc, ppt等。
官方网站：http://npoi.codeplex.com/
nuget直接获取使用
一、NPOI生成Excel
//创建工作薄
var workbook = new HSSFWorkbook();
//创建表
var table = workbook.CreateSheet("joye.net");
//模拟20行20列数据
for (var i = 0; i < 20; i++)
{
var row = table.CreateRow(i);
for (int j = 0; j < 20; j++)
{
var cell = row.CreateCell(j);
cell.SetCellValue(j);
}
}
//打开xls文件，如没有则创建，如存在则在创建是不要打开该文件
using (var fs = File.OpenWrite(@"c:/joye.net.xls"))
{
workbook.Write(fs); //向打开的这个xls文件中写入mySheet表并保存。
Console.WriteLine("生成成功");
}
二、NPOI读取Excel
using (var fs = File.OpenRead(@"c:/joye.net.xls"))
{
//把xls文件中的数据写入workbook1中
var workbook1 = new HSSFWorkbook(fs);
for (var i = 0; i < workbook1.NumberOfSheets; i++)
{
var sheet = workbook1.GetSheetAt(i);
for (var j = 0; j <= sheet.LastRowNum; j++)
{
//读取当前行数据
var row = sheet.GetRow(j);
if (row != null)
{
for (var k = 0; k <= row.LastCellNum; k++)
{ //当前表格
var cell = row.GetCell(k);
if (cell != null)
{
Console.Write(cell.ToString() + " ");
}
}
}
Console.WriteLine();
}
}
}
读出的结果
三、简单学习
/// <summary>
/// 组装workbook.
/// </summary>
/// <param name="dt">dataTable资源</param>
/// <param name="columnHeader">表头</param>
/// <returns></returns>
public static HSSFWorkbook BuildWorkbook1(DataTable dt, string columnHeader = "")
{
var workbook = new HSSFWorkbook();
ISheet sheet = workbook.CreateSheet(string.IsNullOrWhiteSpace(dt.TableName) ? "Sheet1" : dt.TableName);
#region 文件属性信息
{
var dsi = PropertySetFactory.CreateDocumentSummaryInformation();
dsi.Company = "NPOI";
workbook.DocumentSummaryInformation = dsi;
SummaryInformation si = PropertySetFactory.CreateSummaryInformation();
si.Author = "文件作者信息";
si.ApplicationName = "创建程序信息";
si.LastAuthor = "最后保存者信息";
si.Comments = "作者信息";
si.Title = "标题信息";
si.Subject = "主题信息";
si.CreateDateTime = DateTime.Now;
workbook.SummaryInformation = si;
}
#endregion
var dateStyle = workbook.CreateCellStyle();
var format = workbook.CreateDataFormat();
dateStyle.DataFormat = format.GetFormat("yyyy-mm-dd");
//取得列宽
var arrColWidth = new int[dt.Columns.Count];
foreach (DataColumn item in dt.Columns)
{
arrColWidth[item.Ordinal] = Encoding.GetEncoding(936).GetBytes(item.ColumnName.ToString()).Length;
}
for (var i = 0; i < dt.Rows.Count; i++)
{
for (var j = 0; j < dt.Columns.Count; j++)
{
int intTemp = Encoding.GetEncoding(936).GetBytes(dt.Rows[i][j].ToString()).Length;
if (intTemp > arrColWidth[j])
{
arrColWidth[j] = intTemp;
}
}
}
int rowIndex = 0;
foreach (DataRow row in dt.Rows)
{
#region 表头 列头
if (rowIndex == 65535 || rowIndex == 0)
{
if (rowIndex != 0)
{
sheet = workbook.CreateSheet();
}
#region 表头及样式
{
var headerRow = sheet.CreateRow(0);
headerRow.HeightInPoints = 25;
headerRow.CreateCell(0).SetCellValue(columnHeader);
//CellStyle
ICellStyle headStyle = workbook.CreateCellStyle();
headStyle.Alignment = HorizontalAlignment.Center;// 左右居中
headStyle.VerticalAlignment = VerticalAlignment.Center;// 上下居中
// 设置单元格的背景颜色（单元格的样式会覆盖列或行的样式）
headStyle.FillForegroundColor = (short)11;
//定义font
IFont font = workbook.CreateFont();
font.FontHeightInPoints = 20;
font.Boldweight = 700;
headStyle.SetFont(font);
headerRow.GetCell(0).CellStyle = headStyle;
sheet.AddMergedRegion(new CellRangeAddress(0, 0, 0, dt.Columns.Count - 1));
}
#endregion
#region 列头及样式
{
var headerRow = sheet.CreateRow(1);
//CellStyle
ICellStyle headStyle = workbook.CreateCellStyle();
headStyle.Alignment = HorizontalAlignment.Center;// 左右居中
headStyle.VerticalAlignment = VerticalAlignment.Center;// 上下居中
//定义font
IFont font = workbook.CreateFont();
font.FontHeightInPoints = 10;
font.Boldweight = 700;
headStyle.SetFont(font);
foreach (DataColumn column in dt.Columns)
{
headerRow.CreateCell(column.Ordinal).SetCellValue(column.ColumnName);
headerRow.GetCell(column.Ordinal).CellStyle = headStyle;
sheet.SetColumnWidth(column.Ordinal, (arrColWidth[column.Ordinal] + 1) * 256);
}
}
#endregion
if (columnHeader != "")
{
//header row
IRow row0 = sheet.CreateRow(0);
for (int i = 0; i < dt.Columns.Count; i++)
{
ICell cell = row0.CreateCell(i, CellType.String);
cell.SetCellValue(dt.Columns[i].ColumnName);
}
}
rowIndex = 2;
}
#endregion
#region 内容
var dataRow = sheet.CreateRow(rowIndex);
foreach (DataColumn column in dt.Columns)
{
var newCell = dataRow.CreateCell(column.Ordinal);
string drValue = http://www.mamicode.com/row[column].ToString();"System.String"://字符串类型
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);
newCell.SetCellValue(boolV);
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++;
}
//自动列宽
for (int i = 0; i <= dt.Columns.Count; i++)
sheet.AutoSizeColumn(i, true);
return workbook;
}
var dt = new DataTable();
//模拟20行20列数据
for (var i = 0; i < 3; i++)
{
dt.Columns.Add(i.ToString());
}
for (var j = 0; j < 65537; j++)
{
dt.Rows.Add(new object[] { 0 ,1,2 });
}
var newBook = BuildWorkbook(dt);
using (var fs = File.OpenWrite(@"c:/joye.net1.xls"))
{
newBook.Write(fs);
Console.WriteLine("生成成功");
}
四、NPOI导出Excel 65536问题
public static HSSFWorkbook BuildWorkbook(DataTable dt)
{
var book = new HSSFWorkbook();
ISheet sheet = book.CreateSheet("Sheet1");
//Data Rows
for (int i = 0; i < dt.Rows.Count; i++)
{
IRow drow = sheet.CreateRow(i);
for (int j = 0; j < dt.Columns.Count; j++)
{
ICell cell = drow.CreateCell(j, CellType.String);
cell.SetCellValue(dt.Rows[i][j].ToString());
}
}
//自动列宽
for (int i = 0; i <= dt.Columns.Count; i++)
sheet.AutoSizeColumn(i, true);
return book;
}
NPOI导出Excel超过65536会报异常，原来是由于NPOI这个动态库导致的，然后看了下版本，发现是1.2.5。然后百度了下，发现这个版本的NPOI只支持office2003，二office2003最多支持65536行
解决方式：
1、只是在插入数据的时候，加个判断，如果数据条数大于65536时，就在创建一个sheet
//65536判断处理
public static HSSFWorkbook BuildWorkbook(DataTable dt)
{
var book = new HSSFWorkbook();
ISheet sheet1 = book.CreateSheet("Sheet1");
ISheet sheet2 = book.CreateSheet("Sheet2");
//填充数据
for (int i = 0; i < dt.Rows.Count; i++)
{
if (i < 65536)
{
IRow drow = sheet1.CreateRow(i);
for (int j = 0; j < dt.Columns.Count; j++)
{
ICell cell = drow.CreateCell(j, CellType.String);
cell.SetCellValue(dt.Rows[i][j].ToString());
}
}
if (i >= 65536)
{
IRow drow = sheet2.CreateRow(i - 65536);
for (int j = 0; j < dt.Columns.Count; j++)
{
ICell cell = drow.CreateCell(j, CellType.String);
cell.SetCellValue(dt.Rows[i][j].ToString());
}
}
}
//自动列宽
for (int i = 0; i <= dt.Columns.Count; i++)
{
sheet1.AutoSizeColumn(i, true);
sheet2.AutoSizeColumn(i, true);
}
return book;
}
2、考虑使用高版本Office，使用用对象支持高版本的NPOI
//高版本
public static XSSFWorkbook BuildWorkbook(DataTable dt)
{
var book = new XSSFWorkbook();
ISheet sheet = book.CreateSheet("Sheet1");
//Data Rows
for (int i = 0; i < dt.Rows.Count; i++)
{
IRow drow = sheet.CreateRow(i);
for (int j = 0; j < dt.Columns.Count; j++)
{
ICell cell = drow.CreateCell(j, CellType.String);
cell.SetCellValue(dt.Rows[i][j].ToString());
}
}
//自动列宽
for (int i = 0; i <= dt.Columns.Count; i++)
sheet.AutoSizeColumn(i, true);
return book;
}
五、web开发中导出Excel
public static void ExportExcel(DataTable dt, string fileName = "")
{
//生成Excel
IWorkbook book = BuildWorkbook(dt);
//web 下载
if (fileName == "")
fileName = string.Format("{0:yyyyMMddHHmmssffff}", DateTime.Now);
fileName = fileName.Trim();
string ext = Path.GetExtension(fileName);
if (ext.ToLower() == ".xls" || ext.ToLower() == ".xlsx")
fileName = fileName.Replace(ext, string.Empty);
HttpResponse httpResponse = HttpContext.Current.Response;
httpResponse.Clear();
httpResponse.Buffer = true;
httpResponse.Charset = Encoding.UTF8.BodyName;
httpResponse.AppendHeader("Content-Disposition", "attachment;filename=" + fileName + ".xls");
httpResponse.ContentEncoding = Encoding.UTF8;
httpResponse.ContentType = "application/vnd.ms-excel; charset=UTF-8";
book.Write(httpResponse.OutputStream);
httpResponse.End();
}
基于.xls模板生成Excel文件有时间再看
.NET NPOI导出Excel详解
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