2022-06-22 添加多表的导入和导出
2022-03-02 修复读取Excel时 直接读取函数公式
2021-09-30 修复IRow列为空异常
2019-01-14 修复 Excel空行出错
2018-10-27 修复 解决Excel超出DataTable列问题
2018-09-04 修复 导入时间格式问题
导入时间格式问题分析
之前整理的NPOI导入导出Excel 在之前使用过程中没发现问题。
但是后来发现导入的文档如果有日期时间格式，导入时会有混乱
后来找了一下解决方案，最终将其中一段修改即可导入日期(导出未测试)
原因
NPOI导入时会大概判断一下Excel文档里面的单元格是什么格式的内容，
有Blank,Boolean,Numeric,String,Error,Formula 等几种，
但是就是没有日期的，日期的单元格会被判断成Numeric(数字)类型，
所以日期格式的单元格就按数字类型来取其中的值，
所以单元格被判断成数字的之后还要再判断一下是否为日期格式。
2022-03-02 修复读取Excel时 直接读取函数公式
2021-09-30 修复IRow列为空异常
2019-01-14 修复 Excel空行出错
2018-10-27 修复 解决Excel超出DataTable列问题
2018-09-04 修复 导入时间格式问题
导入时间格式问题分析
之前整理的NPOI导入导出Excel 在之前使用过程中没发现问题。
但是后来发现导入的文档如果有日期时间格式，导入时会有混乱
后来找了一下解决方案，最终将其中一段修改即可导入日期(导出未测试)
原因
NPOI导入时会大概判断一下Excel文档里面的单元格是什么格式的内容，
有Blank,Boolean,Numeric,String,Error,Formula 等几种，
但是就是没有日期的，日期的单元格会被判断成Numeric(数字)类型，
所以日期格式的单元格就按数字类型来取其中的值，
所以单元格被判断成数字的之后还要再判断一下是否为日期格式。
以下是核心源码
using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;
using NPOI.XSSF.UserModel;
using System;
using System.Collections.Generic;
using System.Data;
using System.IO;
namespace WindowsFormsApp1
{
/// <summary>
/// 操作Excel通用类
/// </summary>
public class ExcelHelper
{
/// <summary>
/// 从Excel读取数据，只支持单表
/// </summary>
/// <param name="FilePath">文件路径</param>
public static DataTable ReadFromExcel(string FilePath)
{
IWorkbook wk = null;
string extension = System.IO.Path.GetExtension(FilePath); //获取扩展名
try
{
using (FileStream fs = File.OpenRead(FilePath))
{
if (extension.Equals(".xls")) //2003
{
wk = new HSSFWorkbook(fs);
}
else //2007以上
{
wk = new XSSFWorkbook(fs);
}
}
//读取当前表数据
ISheet sheet = wk.GetSheetAt(0);
//构建DataTable
IRow row = sheet.GetRow(0);
DataTable result = BuildDataTable(row);
if (result != null)
{
if (sheet.LastRowNum >= 1)
{
for (int i = 1; i < sheet.LastRowNum + 1; i++)
{
IRow temp_row = sheet.GetRow(i);
if (temp_row == null) { continue; }//2019-01-14 修复 行为空时会出错
List<object> itemArray = new List<object>();
for (int j = 0; j < result.Columns.Count; j++)//解决Excel超出DataTable列问题 lqwvje20181027
{
//itemArray.Add(temp_row.GetCell(j) == null ? string.Empty : temp_row.GetCell(j).ToString());
itemArray.Add(GetValueType(temp_row.GetCell(j)));//解决 导入Excel 时间格式问题 lqwvje 20180904
}
result.Rows.Add(itemArray.ToArray());
}
}
}
return result;
}
catch (Exception ex)
{
return null;
}
}
/// <summary>
/// 从Excel读取数据，支持多表
/// </summary>
/// <param name="FilePath">文件路径</param>
public static DataSet ReadFromExcels(string FilePath)
{
DataSet ds = new DataSet();
IWorkbook wk = null;
string extension = System.IO.Path.GetExtension(FilePath); //获取扩展名
try
{
using (FileStream fs = File.OpenRead(FilePath))
{
if (extension.Equals(".xls")) //2003
{
wk = new HSSFWorkbook(fs);
}
else //2007以上
{
wk = new XSSFWorkbook(fs);
}
}
int SheetCount = wk.NumberOfSheets;//获取表的数量
if (SheetCount < 1)
{
return ds;
}
for (int s = 0; s < SheetCount; s++)
{
//读取当前表数据
ISheet sheet = wk.GetSheetAt(s);
//构建DataTable
IRow row = sheet.GetRow(0);
if (row == null) { continue; }
DataTable tempDT = BuildDataTable(row);
tempDT.TableName = wk.GetSheetName(s);
if (tempDT != null)
{
if (sheet.LastRowNum >= 1)
{
for (int i = 1; i < sheet.LastRowNum + 1; i++)
{
IRow temp_row = sheet.GetRow(i);
if (temp_row == null) { continue; }//2019-01-14 修复 行为空时会出错
List<object> itemArray = new List<object>();
for (int j = 0; j < tempDT.Columns.Count; j++)//解决Excel超出DataTable列问题 lqwvje20181027
{
itemArray.Add(GetValueType(temp_row.GetCell(j)));//解决 导入Excel 时间格式问题 lqwvje 20180904
}
tempDT.Rows.Add(itemArray.ToArray());
}
}
ds.Tables.Add(tempDT);
}
}
return ds;
}
catch (Exception ex)
{
return null;
}
}
/// <summary>
/// 将DataTable数据导入到excel中
/// </summary>
/// <param name="data">要导入的数据</param>
/// <param name="isColumnWritten">DataTable的列名是否要导入</param>
/// <param name="sheetName">要导入的excel的sheet的名称</param>
/// <param name="fileName">导出的文件途径</param>
/// <returns>导入数据行数(包含列名那一行)</returns>
public static int DataTableToExcel(DataTable data, string sheetName, string fileName, bool isColumnWritten=true)
{
IWorkbook workbook = null;
using (FileStream 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();
}
if (workbook == null) { return -1; }
try
{
ISheet sheet = workbook.CreateSheet(sheetName);
int count = 0;
if (isColumnWritten) //写入DataTable的列名
{
IRow row = sheet.CreateRow(0);
for (int j = 0; j < data.Columns.Count; ++j)
{
row.CreateCell(j).SetCellValue(data.Columns[j].ColumnName);
}
count = 1;
}
for (int i = 0; i < data.Rows.Count; ++i)
{
IRow row = sheet.CreateRow(count);
for (int 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;
}
}
}
/// <summary>
/// 将DataSet数据导入到excel中 每个datatable一个sheet,sheet名为datatable名
/// </summary>
/// <param name="ds">要导入的数据</param>
/// <param name="isColumnWritten">DataTable的列名是否要导入</param>
/// <param name="fileName">导出的文件途径</param>
public static bool DataTableToExcel(DataSet ds, string fileName, bool isColumnWritten=true)
{
if (ds == null || ds.Tables.Count < 1)
{
return false;
}
IWorkbook workbook = null;
using (FileStream 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();
}
if (workbook == null) { return false; }
try
{
foreach (DataTable dt in ds.Tables)
{
ISheet sheet = workbook.CreateSheet(dt.TableName);
if (isColumnWritten) //写入DataTable的列名
{
IRow row = sheet.CreateRow(0);
for (int j = 0; j < dt.Columns.Count; ++j)
{
row.CreateCell(j).SetCellValue(dt.Columns[j].ColumnName);
}
}
for (int i = 0; i < dt.Rows.Count; ++i)
{
IRow row = sheet.CreateRow(isColumnWritten ? i + 1 : i);
for (int j = 0; j < dt.Columns.Count; ++j)
{
row.CreateCell(j).SetCellValue(dt.Rows[i][j].ToString());
}
}
}
workbook.Write(fs); //写入到excel
}
catch (Exception ex)
{
Console.WriteLine("Exception: " + ex.Message);
return false;
}
}
return true;
}
private static DataTable BuildDataTable(IRow Row)
{
DataTable result = null;
if (Row.Cells.Count > 0)
{
result = new DataTable();
for (int i = 0; i < Row.LastCellNum; i++)
{
if (Row.GetCell(i) != null)
{
result.Columns.Add(Row.GetCell(i).ToString());
}
}
}
return result;
}
/// <summary>
/// 获取单元格类型
/// </summary>
/// <param name="cell"></param>
/// <returns></returns>
private static object GetValueType(ICell cell)
{
if (cell == null)
return null;
switch (cell.CellType)
{
case CellType.Blank: //BLANK:
return null;
case CellType.Boolean: //BOOLEAN:
return cell.BooleanCellValue;
case CellType.Numeric: //NUMERIC:
if (DateUtil.IsCellDateFormatted(cell))
{
return cell.DateCellValue;
}
return cell.NumericCellValue;
case CellType.String: //STRING:
return cell.StringCellValue;
case CellType.Error: //ERROR:
return cell.ErrorCellValue;
case CellType.Formula: //FORMULA:
cell.SetCellType(CellType.String);
return cell.StringCellValue;
default:
return "=" + cell.CellFormula;
}
}
}
}
以下是调用上面导入导出的方法
private void button2_Click(object sender, EventArgs e)
{
DataTable data = new DataTable();
DataColumn dc = new DataColumn("姓名");
DataColumn dc2 = new DataColumn("年龄");
DataColumn dc3 = new DataColumn("性别");
data.Columns.Add(dc);
data.Columns.Add(dc2);
data.Columns.Add(dc3);
DataRow row1 = data.NewRow();
row1["姓名"] = "张三";
row1["年龄"] = 19;
row1["性别"] = "男";
data.Rows.Add(row1);
DataRow row2 = data.NewRow();
row2["姓名"] = "李四";
row2["年龄"] = 20;
row2["性别"] = "男";
data.Rows.Add(row2);
FolderBrowserDialog folder = new FolderBrowserDialog();
if (folder.ShowDialog() == DialogResult.OK)
{
string ExportDir = folder.SelectedPath + "\\数据导出" + DateTime.Now.ToString("yyyyMMddHHmmss") + ".xlsx";
int i = ExcelHelper.DataTableToExcel(data, "测试", ExportDir, true);
MessageBox.Show(i.ToString());
}
}
private void button3_Click(object sender, EventArgs e)
{
OpenFileDialog openFile = new OpenFileDialog();
if (openFile.ShowDialog() == DialogResult.OK)
{
string filePath = openFile.FileName;
DataTable excelDt = ReadFromExcel(filePath);
//把Excel读取到DataTable里面 然后再把DataTable存入数据库
}
}