一、nuget安装

  <ItemGroup><PackageReference Include="Spire.PDF" Version="10.6.7" /></ItemGroup>

二、直接上代码

using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Logging;
using System;
using System.IO;namespace pdfdemo.Controllers
{public class HomeController : Controller{private readonly ILogger<HomeController> _logger;public HomeController(ILogger<HomeController> logger){_logger = logger;}public IActionResult Index(){var path = $"{AppDomain.CurrentDomain.BaseDirectory}/133634930918199804.pdf";var imgPath = $"{AppDomain.CurrentDomain.BaseDirectory}/1336349309181998041.png";using (Spire.Pdf.PdfDocument document = new Spire.Pdf.PdfDocument()){using (var stream = new FileStream(path, FileMode.Open, FileAccess.Read)){document.LoadFromStream(stream);using (var memoryStream = new System.IO.MemoryStream()){document.SaveToImageStream(0, memoryStream, "image/png");System.IO.File.WriteAllBytes(imgPath, memoryStream.ToArray());}}}return View();}}
}

运行效果：