用C#读取EXCEL文件文本

之前开发搜索软件的时候用到，需要查找EXCEL文件里面是否含有一些关键字。

需要先安装NPOI：

Install-Package NPOI

示例代码：

using NPOI.SS.UserModel;
using System;
using System.Collections.Generic;
using System.Data;
using System.IO;
using System.Text;

namespace CgdataBase
{
    public class ExcelHelper
    {
        private static IWorkbook OpenWorkbook(string fileName)
        {
            FileStream file = new FileStream(fileName, FileMode.Open, FileAccess.Read);
            return WorkbookFactory.Create(file, true);
        }

        public static string ReadAllText(string fileName)
        {
            var myList = new StringBuilder();

            IWorkbook workbook = OpenWorkbook(fileName);
            for (int i = 0; i < workbook.NumberOfSheets; i++)
            {
                ISheet sheet = workbook.GetSheetAt(i);
                if (sheet != null)
                {
                    myList.Append(ReadAllText(sheet));
                }
            }

            return myList.ToString();
        }

        private static string ReadAllText(ISheet sheet)
        {
            var myList = new StringBuilder();
            for (int i = sheet.FirstRowNum; i <= sheet.LastRowNum; i++)
            {
                IRow row = sheet.GetRow(i);
                if (row != null)
                {
                    for (int j = row.FirstCellNum; j <= row.LastCellNum; j++)
                    {
                        var cell = row.GetCell(j);
                        if (cell?.CellType == CellType.String)
                        {
                            myList.Append(cell.StringCellValue);
                        }
                    }
                }
            }

            return myList.ToString();
        }
    }
}