C#经常操作excel使用的NPOI帮助类
1、nuget NPOI
2、excel帮助类代码如下：
using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;
using NPOI.XSSF.UserModel;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Data;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Web;
namespace excel
{
public class ExcelHelp : IDisposable
{
private string fileName = null; //文件名
private IWorkbook workbook = null;
private FileStream fs = null;
private bool disposed;
public ExcelHelp(string fileName)
{
this.fileName = fileName;
disposed = false;
}
///
/// 将DataTable数据导入到excel中
///
/// 要导入的数据
/// DataTable的列名是否要导入
/// 要导入的excel的sheet的名称
/// 导入数据行数(包含列名那一行)
public int DataTableToExcel(DataTable data, string sheetName, bool isColumnWritten)
{
int i = 0;
int j = 0;
int count = 0;
ISheet sheet = null;
fs = new FileStream(fileName, FileMode.OpenOrCreate, FileAccess.ReadWrite);
if (fileName.IndexOf(".xlsx") > 0) // 2007版本
workbook = new XSSFWorkbook();
else if (fileName.IndexOf(".xls") > 0) // 2003版本
workbook = new HSSFWorkbook();
try
{
if (workbook != null)
{
sheet = workbook.CreateSheet(sheetName);
}
else
{
return -1;
}
if (isColumnWritten == true) //写入DataTable的列名
{
IRow row = sheet.CreateRow(0);
for (j = 0; j < data.Columns.Count; ++j)
{
row.CreateCell(j).SetCellValue(data.Columns[j].ColumnName);
}
count = 1;
}
else
{
count = 0;
}
for (i = 0; i < data.Rows.Count; ++i)
{
IRow row = sheet.CreateRow(count);
for (j = 0; j < data.Columns.Count; ++j)
{
row.CreateCell(j).SetCellValue(data.Rows[i][j].ToString());
}
++count;
}
workbook.Write(fs); //写入到excel
return count;
}
catch (Exception ex)
{
Console.WriteLine("Exception: " + ex.Message);
return -1;
}
}
///
/// 将excel中的数据导入到DataTable中
///
/// excel工作薄sheet的名称
/// 第一行是否是DataTable的列名
/// 返回的DataTable
public DataTable ExcelToDataTable(string sheetName, bool isFirstRowColumn)
{
ISheet sheet = null;
DataTable data = new DataTable();
int startRow = 0;
try
{
fs = new FileStream(fileName, FileMode.Open, FileAccess.Read);
if (fileName.IndexOf(".xlsx") > 0) // 2007版本
workbook = new XSSFWorkbook(fs);
else if (fileName.IndexOf(".xls") > 0) // 2003版本
workbook = new HSSFWorkbook(fs);
if (sheetName != null)
{
sheet = workbook.GetSheet(sheetName);
if (sheet == null) //如果没有找到指定的sheetName对应的sheet，则尝试获取第一个sheet
{
sheet = workbook.GetSheetAt(0);
}
}
else
{
sheet = workbook.GetSheetAt(0);
}
if (sheet != null)
{
IRow firstRow = sheet.GetRow(0);
if (firstRow==null)
{
return null;
}
int cellCount = firstRow.LastCellNum; //一行最后一个cell的编号 即总的列数
if (isFirstRowColumn)
{
for (int i = firstRow.FirstCellNum; i < cellCount; ++i)
{
ICell cell = firstRow.GetCell(i);
if (cell != null)
{
cell.SetCellType(CellType.String);
string cellValue = cell.StringCellValue;
if (cellValue != null)
{
DataColumn column = new DataColumn(cellValue);
data.Columns.Add(column);
}
}
}
startRow = sheet.FirstRowNum + 1;
}
else
{
startRow = sheet.FirstRowNum;
}
//最后一列的标号
int rowCount = sheet.LastRowNum;
for (int i = startRow; i <= rowCount; ++i)
{
IRow row = sheet.GetRow(i);
if (row == null) continue; //没有数据的行默认是null
DataRow dataRow = data.NewRow();
for (int j = row.FirstCellNum; j < cellCount; ++j)
{
ICell cell = row.GetCell(j);
if (cell!=null&&cell.CellType == CellType.Numeric && DateUtil.IsCellDateFormatted(cell))
dataRow[j] = cell.DateCellValue.ToString("yyyy/MM/dd");
else
{
//dataRow[j] = row.GetCell(j).ToString();
if (row.GetCell(j) != null) //同理，没有数据的单元格都默认是null
dataRow[j] = row.GetCell(j).ToString();
}
}
data.Rows.Add(dataRow);
}
}
return data;
}
catch (Exception ex)
{
Console.WriteLine("Exception: " + ex.Message);
return null;
}
}
public void Dispose()
{
Dispose(true);
GC.SuppressFinalize(this);
}
protected virtual void Dispose(bool disposing)
{
if (!this.disposed)
{
if (disposing)
{
if (fs != null)
fs.Close();
}
fs = null;
disposed = true;
}
}
///
/// 字符串日期转DateTime
///
public static DateTime TransStrToDateTime(string strDateTime)
{
DateTime now;
string[] format = new string[]
{
"yyyyMMddHHmmss", "yyyy-MM-dd HH:mm:ss", "yyyy年MM月dd日 HH时mm分ss秒",
"yyyyMdHHmmss","yyyy年M月d日 H时mm分ss秒", "yyyy.M.d H:mm:ss", "yyyy.MM.dd HH:mm:ss","yyyy-MM-dd","yyyyMMdd"
,"yyyy/MM/dd","yyyy/M/d","yyyy/M/dd","dd-MM月-yyyy"
};
if (DateTime.TryParseExact(strDateTime, format, CultureInfo.InvariantCulture, DateTimeStyles.None, out now))
{
return now;
}
return DateTime.MinValue;
}
//循环去除datatable中的空行
public DataTable removeEmpty(DataTable dt)
{
List removelist = new List();
for (int i = 0; i < dt.Rows.Count; i++)
{
bool rowdataisnull = true;
for (int j = 0; j < dt.Columns.Count; j++)
{
if (!string.IsNullOrEmpty(dt.Rows[i][j].ToString().Trim()))
{
rowdataisnull = false;
}
}
if (rowdataisnull)
{
removelist.Add(dt.Rows[i]);
}
}
for (int i = 0; i < removelist.Count; i++)
{
dt.Rows.Remove(removelist[i]);
}
return dt;
}
}
} 3、如何使用如下：
try
{
using (ExcelHelp excelHelper = new ExcelHelp(文件全路径))
{
DataTable dt = excelHelper.ExcelToDataTable(null, true);
if (dt != null && dt.Rows.Count > 0)
{
foreach (DataRow item in dt.Rows)
{
try
{
var 列名 = item["列名"].ToString();
}
catch (Exception ex)
{
}
}
}
}
}
catch (Exception ex)
{
msg = ex.Message.ToString();
Console.WriteLine("Exception: " + ex.Message);
}