C# NPOI读取xlsx的方法

使用NPOI读取xlsx文件可以按照以下步骤：

1. 引入NPOI的命名空间

using NPOI.SS.UserModel;
using NPOI.XSSF.UserModel;

2. 创建一个XSSFWorkbook对象来代表整个Excel文件

XSSFWorkbook workbook = new XSSFWorkbook(@"D:\example.xlsx");

3. 获取Excel中的第一个Sheet

ISheet sheet = workbook.GetSheetAt(0);

4. 遍历Sheet中的每一行，获取该行中的每一列的值

for (int i = 0; i <= sheet.LastRowNum; i++)
{
    IRow row = sheet.GetRow(i);

    if (row != null)
    {
        for (int j = 0; j < row.LastCellNum; j++)
        {
            string value = row.GetCell(j)?.ToString();
            Console.Write($"{value}\t");
        }
        Console.WriteLine();
    }
}

完整代码示例：

using System;
using NPOI.SS.UserModel;
using NPOI.XSSF.UserModel;

namespace ReadExcelDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            XSSFWorkbook workbook = new XSSFWorkbook(@"D:\example.xlsx");
            ISheet sheet = workbook.GetSheetAt(0);

            for (int i = 0; i <= sheet.LastRowNum; i++)
            {
                IRow row = sheet.GetRow(i);

                if (row != null)
                {
                    for (int j = 0; j < row.LastCellNum; j++)
                    {
                        string value = row.GetCell(j)?.ToString();
                        Console.Write($"{value}\t");
                    }
                    Console.WriteLine();
                }
            }

            Console.ReadLine();
        }
    }
}