1、安装引用DotNetCore.NPOI
1）使用Nuget界面管理器
搜索"DotNetCore.NPOI",在列表中找到它，点击 "安装"
相关文档：VS(Visual Studio)中Nuget的使用
2）使用Package Manager命令安装
PM> Install-Package DotNetCore.NPOI
3）使用.NET CLI命令安装
> dotnet add TodoApi.csproj package DotNetCore.NPOI
2、使用NPOI创建Excel的示例代码
命名空间：
using NPOI.SS.UserModel;
using NPOI.XSSF.UserModel;
using System;
using System.Data;
using System.IO;
示例代码：
public static void TransferXLToTable(){ DataTable dt = new DataTable(); dt.Columns.Add("City", typeof(string)); dt.Columns.Add("State", typeof(string)); dt.Columns.Add("Zip", typeof(string)); // using (FileStream stream = new FileStream(@"C:\Working\source.xlsx", FileMode.Open, FileAccess.Read)) { IWorkbook wb = new XSSFWorkbook(stream); ISheet sheet = wb.GetSheet("Sheet1"); string holder; int i = 0; do { DataRow dr = dt.NewRow(); IRow row = sheet.GetRow(i); try { holder = row.GetCell(0, MissingCellPolicy.CREATE_NULL_AS_BLANK).ToString(); } catch (Exception) { break; } string city = holder.Substring(0, holder.IndexOf(',')); string state = holder.Substring(holder.IndexOf(',') + 2, 2); string zip = holder.Substring(holder.IndexOf(',') + 5, 5); dr[0] = city; dr[1] = state; dr[2] = zip; dt.Rows.Add(dr); i++; } while (!String.IsNullOrEmpty(holder)); } using (FileStream stream = new FileStream(@"C:\Working\FieldedAddresses.xlsx", FileMode.Create, FileAccess.Write)) { IWorkbook wb = new XSSFWorkbook(); ISheet sheet = wb.CreateSheet("Sheet1"); ICreationHelper cH = wb.GetCreationHelper(); for (int i = 0; i < dt.Rows.Count; i++) { IRow row = sheet.CreateRow(i); for (int j = 0; j < 3; j++) { ICell cell = row.CreateCell(j); cell.SetCellValue(cH.CreateRichTextString(dt.Rows[i].ItemArray[j].ToString())); } } wb.Write(stream); }} var demoService = provider.GetRequiredService(); Console.WriteLine($"Output: {demoService.HelloWorld()}"); Console.ReadKey();}